Practical Work

Solutions for Chemistry, Class 10, ICSE

Exercise 13 Long Answer Type

2 questions

Question 1

When an ammonium salt is warmed with sodium hydroxide solution, ammonia gas is evolved. State three ways in which you could identify this gas.

Exercise 13 Long Answer Type

Answer:

The three ways to identify ammonia gas are:

  1. Ammonia gas turns moist red litmus turns blue.
  2. If a glass rod dipped in concentrated HCl is brought near the gas, dense white fumes of ammonium chloride are formed.
  3. The gas turns colourless Nessler's reagent i.e. K2HgI4 potassium mercuric iodide brown.

Question 2

Give a chemical test to distinguish between :

(a) Sodium chloride soln. and sodium nitrate soln.

(b) Hydrogen chloride gas and hydrogen sulphide gas.

(c) Calcium nitrate soln. and zinc nitrate soln.

(d) Carbon dioxide gas and sulphur dioxide gas.

(e) Sodium carbonate and sodium sulphite

(f) Ferrous nitrate and lead nitrate.

(g) Manganese dioxide and copper (Il) oxide.

(h) Sodium nitrate and sodium sulphite [using dilute sulphuric acid].

(i) Sodium chloride and sodium sulphide

(j) Sodium hydroxide solution and ammonium hydroxide solution.

(k) Ammonium sulphate and sodium sulphate.

(l) Sulphuric acid from nitric acid and hydrochloric acid.

(m) Magnesium chloride and magnesium nitrate solution

(n) Zinc sulphate solution and zinc chloride solution

(o) Iron (II) chloride soln. and iron (III) chloride soln.

(p) Calcium nitrate soln. and calcium chloride soln.

Exercise 13 Long Answer Type

Answer:

(a) Add silver nitrate soln. to the given solns., sodium chloride reacts to form a white ppt. which is soluble in NH4OH and insoluble in dil. HNO3. The other soln. is sodium nitrate.

NaCl + AgNO3 ⟶ AgCl ↓ [white ppt.] + NaNO3

NaNO3 + AgNO3 ⟶ no white ppt.

(b) Hydrogen sulphide gas turns moist lead acetate paper silvery black or black whereas, no change is observed in case of HCl gas.

Pb(CH3COO)2 [colourless] + H2S ⟶ PbS [black] + 2CH3COOH

(c) When NaOH is added to the given soln., Zn(NO3)2 reacts to form a gelatinous white ppt. which dissolves in excess of NaOH whereas, Ca(NO3)2 forms a milky white ppt. which is insoluble in excess of NaOH. Hence, the two can be distinguished.

(d) Carbon dioxide gas has no effect on acidified potassium permanganate (KMnO4) and acidified potassium dichromate (K2Cr2O7) solution whereas sulphur dioxide gas turns acidified potassium permanganate from pink to clear colourless and acidified potassium dichromate from orange to clear green.

2KMnO4 + 2H2O + 5SO2 ⟶ K2SO4 + 2MnSO4 + 2H2SO4

K2Cr2O7 + H2SO4 + 3SO2 ⟶ K2SO4 + Cr2(SO4)3 + H2O

(e) When dil. sulphuric acid is added to sodium carbonate and heated, colourless, odourless gas is evolved which turns lime water milky and has no effect on KMnO4 or K2Cr2O7 solutions.

When dil. sulphuric acid is added to sodium sulphite and heated, colourless gas with suffocating odour is evolved which turns lime water milky. It turns acidified K2Cr2O7 from orange to clear green and pink coloured KMnO4 to clear colourless.

Hence, the two compounds can be distinguished.

(f) When NaOH is added to each of the compounds, a dirty green precipitate of Iron [II] hydroxide [Fe(OH)2] is formed in case of Ferrous nitrate whereas a chalky white precipitate of lead hydroxide [Pb(OH)2] is formed in case of lead nitrate. Iron [II] Hydroxide [Fe(OH)2] is insoluble in excess of NaOH, whereas Lead Hydroxide [Pb(OH)2] is soluble in excess of NaOH. Hence, the two compounds can be distinguished.

(g) When each of the compound is heated with conc. hydrochloric acid, greenish yellow (chlorine) gas is evolved in case of manganese dioxide and filtrate is brownish in colour whereas, no chlorine gas is evolved in case of copper (II) oxide and filtrate is bluish in colour.

MnO2 + 4HCl ⟶ MnCl2 + 2H2O + Cl2

CuO + 2HCl ⟶ CuCl2 + H2O

(h) Sodium nitrate will not react with dilute sulphuric acid.

Sodium sulphite reacts with dil. sulphuric acid and colourless gas with suffocating odour is evolved which turns lime water milky.

(i) When dil. sulphuric acid is added to sodium sulphide and heated, hydrogen sulphide gas is evolved which has the smell of rotten eggs and turns lead acetate paper black.
Whereas, when conc. sulphuric acid is added to sodium chloride and heated, HCl gas is evolved which gives dense white fumes when a glass rod dipped in ammonia is brought near it.

(j) When ammonium hydroxide is reacted with a solution of copper sulphate, a pale blue ppt. of copper hydroxide is formed which dissolves in excess of ammonium hydroxide forming a deep blue solution of a soluble complex salt [Cu(NH3)4]SO4 [tetramine copper [II] sulphate] .

CuSO4 + 2NH4OH ⟶ (NH4)2SO4 + Cu(OH)2

Cu(OH)2 + (NH4)2SO4 + 2NH4OH ⟶ [Cu(NH3)4]SO4 + 4H2O

Whereas, when copper sulphate is added to sodium hydroxide solution, pale blue ppt. of copper hydroxide is obtained which is insoluble in excess of sodium hydroxide.

CuSO4 + 2NaOH ⟶ Na2SO4 + Cu(OH)2

(k) When ammonium sulphate is heated with NaOH, ammonia gas is produced which turns red litmus blue whereas, sodium sulphate does not react with sodium hydroxide.

(NH4)2SO4 + 2NaOH ⟶ Na2SO4 + 2H2O + 2NH3

Na2SO4 + NaOH ⟶ no reaction.

(l) Barium chloride reacts with dil H2SO4 to form a white ppt. of barium sulphate.

BaCl2 + H2SO4 [dil.] ⟶ 2HCl + BaSO4 ↓ [white ppt.]

Whereas, HCl and nitric acid does not form a white ppt.

BaCl2 + HCl ⟶ No white ppt.

BaCl2 + HNO3 ⟶ No white ppt

(m) Add silver nitrate solution to the given solns., magnesium chloride reacts to form a white ppt of silver chloride (AgCl). Whereas, magnesium nitrate show no reaction with silver nitrate. Hence, they can be distinguished using silver nitrate.

MgCl2 + 2AgNO3 ⟶ 2AgCl↓ + Mg(NO3)2

(n) When BaCl2 soln. is added to ZnSO4, a white ppt. of BaSO4 is formed, whereas, no ppt. is formed in case of ZnCl2. Hence, the two solns. can be distinguished.

BaCl2 + ZnSO4 ⟶ BaSO4 ↓ [white ppt.] + ZnCl2

BaCl2 + ZnCl2 ⟶ No white ppt.

(o) When NaOH soln. is added to the given solns., FeCl2 reacts to form a dirty green ppt. of Fe(OH)2 whereas, FeCl3 reacts to form a reddish brown ppt. of Fe(OH)3.

(p) Add silver nitrate soln. to the given solns., calcium chloride reacts to form a white ppt. which is soluble in NH4OH and insoluble in dil. HNO3. The other soln. is calcium nitrate.

CaCl2 + 2AgNO3 ⟶ 2AgCl ↓ [white ppt.] + Ca(NO3)2

Ca(NO3)2 + AgNO3 ⟶ no white ppt.

Exercise 13 Multiple Choice Type

13 questions

Question 1

Carbon dioxide and sulphur dioxide gas can be distinguished by using

  1. moist blue litmus paper
  2. lime water
  3. acidified potassium dichromate paper
  4. none of the above.
Exercise 13 Multiple Choice Type

Answer:

acidified K2Cr2O7 (potassium dichromate) paper

Reason

There is no effect of CO2 gas on potassium dichromate whereas SO2 turns acidified potassium dichromate from orange to clear green.

K2Cr2O7 + H2SO4 + 3SO2 ⟶ K2SO4 + Cr2(SO4)3 + H2O

Question 2

The salt which in solution gives a pale green precipitate with sodium hydroxide solution and a white precipitate with barium chloride solution is :

  1. Iron (III) sulphate
  2. Iron (II) sulphate
  3. Iron (II) chloride
  4. Iron (III) chloride
Exercise 13 Multiple Choice Type

Answer:

Iron (II) sulphate

Reason

  1. Pale green precipitate with sodium hydroxide (NaOH):
    • Iron (II) salts (like Iron (II) sulphate) give a pale green precipitate of iron (II) hydroxide, Fe(OH)2:
      FeSO4 + 2NaOH ⟶ Fe(OH)2↓ (pale green) + Na2SO4
    • Iron (III) salts would give a reddish-brown precipitate instead (Fe(OH)3)
  2. White precipitate with barium chloride (BaCl2):
    • The sulphate ion (SO42-) reacts with barium chloride to form barium sulphate (BaSO4), a white precipitate:
      FeSO4 + BaCl2 ⟶ BaSO4↓ (white) + FeCl2
    • This confirms the presence of a sulphate ion in the salt.

So, the salt must be an iron (II) salt (due to the pale green ppt) containing sulphate (due to white ppt with BaCl2), i.e., Iron (II) sulphate.

Question 3

A compound P is heated in a test tube with sodium hydroxide solution. A red litmus paper held at the mouth of the test tube turns blue. Which of the following could compound P be?

  1. Zinc sulphate
  2. Copper sulphate
  3. Ferrous sulphate
  4. Ammonium sulphate
Exercise 13 Multiple Choice Type

Answer:

Ammonium sulphate

Reason — Ammonium sulphate reacts with sodium hydroxide to produce sodium sulphate, ammonia gas, and water. The red litmus turns blue due to the basic ammonia gas.

Question 4

Aqueous lead (II) nitrate can be distinguished from aqueous zinc nitrate by adding any of the following solution in excess, except:

  1. aqueous potassium chloride
  2. aqueous sodium sulphate
  3. dilute sulphuric acid
  4. sodium hydroxide solution
Exercise 13 Multiple Choice Type

Answer:

sodium hydroxide solution

Reason — Let's analyze each option:

  1. Aqueous potassium chloride: This will precipitate lead(II) chloride (PbCl₂) from lead (II) nitrate, whereas zinc chloride is soluble. Thus, this can distinguish between them, as lead will form a precipitate while zinc will not.

  2. Aqueous sodium sulphate: This will precipitate lead (II) sulphate (PbSO₄) from lead (II) nitrate since PbSO₄ is poorly soluble, while zinc sulphate is soluble. Thus, this can also distinguish between them.

  3. Dilute sulphuric acid: Similar to aqueous sodium sulphate, adding dilute H₂SO₄ will precipitate lead (II) sulphate from lead (II) nitrate but not zinc sulphate from zinc nitrate. So, this can distinguish between them.

  4. Sodium hydroxide solution: When added to both solutions in excess, this will not distinguish them because both lead (II) hydroxide and zinc hydroxide will initially precipitate but then both dissolve upon further addition of NaOH. Lead hydroxide forms a plumbate ion, and zinc hydroxide forms a zincate ion, both of which are soluble.

Question 5

A student takes Cu, Al, Fe and Zn strips, separately in four test tubes labeled as I, II, III and IV respectively. He adds 10 ml of freshly prepared ferrous sulphate solution to each test tube and observes the colour of the metal residue in each case.

A student takes Cu, Al, Fe and Zn strips, separately in four test tubes labeled as I, II, III and IV respectively. He adds 10 ml of freshly prepared ferrous sulphate solution to each test tube and observes the colour of the metal residue in each case. ICSE 2025 Chemistry Solved Question Paper.

He would observe a black residue in the test tubes:

  1. (I) and (II)
  2. (I) and (III)
  3. (II) and (III)
  4. (II) and (IV)
Exercise 13 Multiple Choice Type

Answer:

(II) and (IV)

Reason — Zinc and aluminium are more reactive than iron. Therefore they will displace iron which will be seen as black residue.

Question 6

A nitrate which forms a precipitate with ammonium hydroxide and is also soluble in excess of it:

  1. ferrous nitrate
  2. ferric nitrate
  3. lead nitrate
  4. copper nitrate
Exercise 13 Multiple Choice Type

Answer:

copper nitrate

Reason — When copper nitrate reacts with ammonium hydroxide NH4OH, it initially forms a light blue precipitate of copper(II) hydroxide (Cu(OH)2).
This precipitate is soluble in excess ammonium hydroxide due to the formation of a deep blue complex, tetraamminecopper(II) ([Cu(NH3)4]2+), making it soluble.

Question 7

Dilute sulphuric acid is added to sodium sulphite. The following observations are noticed:

P — A gas with a suffocating smell is evolved which turns lime water milky.

Q — A foul smelling gas is evolved which turns lead acetate solution black.

R — A gas is evolved which decolourises pink KMnO4

Which of the following is true?

  1. Only P
  2. Only Q
  3. Only R
  4. Both P and R
Exercise 13 Multiple Choice Type

Answer:

Both P and R

Reason — When dilute sulphuric acid is added to sodium sulphite, a colourless gas with a smell of burning sulphur i.e., suffocating odour is evolved.

Na2SO3 + H2SO4 ⟶ Na2SO4 + H2O + SO2

This gas turns lime water milky.

Ca(OH)2 + SO2 ⟶ CaSO3↓ + H2O

This gas also decolourises pink KMnO4.

2KMnO4 + 2H2O + 5SO2 ⟶ K2SO4 + 2MnSO4 + 2H2SO4

Question 8

A compound X consists of molecules. Which of the following properties will be shown by X?

P — The boiling point of X is low.

Q — The compound X is soluble in water.

R — The aqueous solution of X does not conduct electricity.

  1. Only P
  2. Only Q
  3. Only R
  4. Both P and R
Exercise 13 Multiple Choice Type

Answer:

Both P and R

Reason — Molecular compounds usually have weak intermolecular forces, leading to low boiling points. Molecular compounds typically do not form ions in solution (unless they’re acids or bases). So their solutions are usually non-conducting. Most covalent compounds are insoluble in water, unless they are polar.

Question 9

Assertion (A): HCl can be tested by AgNO3 solution.

Reason (R): White precipitate of AgCl is formed when AgNO3 is added to HCl.

  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false but R is true.
Exercise 13 Multiple Choice Type

Answer:

Both A and R are true and R is the correct explanation of A.

Explanation— HCl can be tested by AgNO3 solution. When, HCl gas is passed through Silver nitrate solution white precipitate of AgCl is formed.

AgNO3(aq) + HCl ⟶ AgCl↓ + HNO3

Hence, both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Question 10

Assertion (A): SO2 and CO2 can be distinguished by lime water.

Reason (R): Both turn lime water milky.

  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false but R is true.
Exercise 13 Multiple Choice Type

Answer:

A is false but R is true.

Explanation— SO2 and CO2 cannot be distinguished by lime water, because both turn lime water milky. Hence, the assertion (A) is false.

Ca(OH)2 + SO2 ⟶ CaSO3↓ + H2O

Ca(OH)2 + CO2 ⟶ CaCO3↓ + H2O

SO2 and CO2 turn lime water milky. Hence, the reason (R) is true.

Question 11

Assertion (A): On passing H2S through lead nitrate solution, a black precipitate is formed.

Reason (R): Lead nitrate reacts with H2S to form a black precipitate of PbS.

  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false but R is true.
Exercise 13 Multiple Choice Type

Answer:

Both A and R are true and R is the correct explanation of A.

Explanation— H2S is colourless gas having a foul smell of rotten eggs. When H2S is passed through lead nitrate solution, a black precipitate of PbS is formed.

Pb(NO3)2 + H2S ⟶ PbS ↓ + 2HNO3

Hence, both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Question 12

Assertion (A): Chloride can be tested by adding concentrated sulphuric acid to it. A colourless gas with a pungent odour is evolved.

Reason (R): The gas formed is chlorine.

  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false but R is true.
Exercise 13 Multiple Choice Type

Answer:

A is true but R is false.

Explanation— The presence of chloride ion can be tested by adding concentrated sulphuric acid. It is observed that the colourless HCl gas of pungent odour is evolved. Hence, the assertion (A) is true.

The colourless gas evolved in the above reaction is HCl. Hence, the reason (R) is false.

Question 13

Assertion (A): If barium nitrate solution is added to sodium sulphate solution, a white precipitate is formed.

Reason (R): Sodium sulphate solution is white in colour.

  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false but R is true.
Exercise 13 Multiple Choice Type

Answer:

A is true but R is false.

Explanation— When barium nitrate solution is added to sodium sulphate salt solution, white precipitate which is insoluble in water is formed. White precipitate is soluble in dil. HCl. Hence, the assertion (A) is true.

Sodium sulphate solution is a colourless solution. Hence, the reason (R) is false.

Exercise 13 Short Answer Type

11 questions

Question 1

Name the anion present in each of the following compounds.

(a) Compound A when warmed with concentrated sulphuric acid gives a gas which fumes in moist air and which gives dense white fumes with ammonia.

(b) When barium chloride solution is added to a solution of compound B, a white precipitate insoluble in dilute hydrochloric acid is formed.

(c) The action of heat on the insoluble compound C produces a gas which turns lime water turbid.

(d) Compound D when warmed with dilute sulphuric acid gives a gas which turns acidified dichromate solution green.

Exercise 13 Short Answer Type

Answer:

(a) Cl-

(b) SO42-

(c) CO32-

(d) SO32-

Question 2

A given white crystalline salt was tested as follows :

(a) It dissolved in water and the resulting solution of the salt turned blue litmus red.

(b) Addition of barium chloride solution into this solution gave a white precipitate.

(c) A flame test on the salt gave a persistent golden-yellow colourisation.

What conclusion can be drawn for each observation?

Exercise 13 Short Answer Type

Answer:

(a) As the salt solution turned blue litmus red hence the salt may be an acid.

(b) As white ppt. is obtained on addition of barium chloride so the salt may contain SO42-, SO32-, CO32-.

(c) Persistent golden yellow colourisation which suggests presence of Na+ ion.

Question 3

(a) Sodium hydroxide solution is added to solution A. A white precipitate is formed which is insoluble in excess sodium hydroxide solution. Name the metal ion present in solution A.

(b) When ammonium hydroxide is added to solution B, a pale blue precipitate is formed. This pale blue precipitate dissolves in excess ammonium hydroxide giving an inky blue solution. Name the cation present in solution B.

Exercise 13 Short Answer Type

Answer:

(a) Ca2+

(b) Cu+

Question 4

The questions (i) to (v) refer to the following salt solutions listed A to F.

A. Copper nitrate

B. Iron (II) sulphate

C. Iron (III) chloride

D. Lead nitrate

E. Magnesium sulphate

F. Zinc chloride

(i) Which two solutions will give a white precipitate when treated with dilute hydrochloric acid followed by barium chloride solution?

(ii) Which two solutions will give a white precipitate when treated with dilute nitric acid followed by silver nitrate solution?

(iii) Which solution will give a white precipitate, when either dilute hydrochloric acid or dilute sulphuric acid is added to it?

(iv) Which solution becomes a deep/inky blue colour when excess of ammonium hydroxide is added to it?

(v) Which solution gives a white precipitate with excess ammonium hydroxide solution?

Exercise 13 Short Answer Type

Answer:

(i) Iron (II) Sulphate and Magnesium sulphate

(ii) Iron (III) chloride and Zinc Chloride

(iii) Lead nitrate

(iv) Copper nitrate.

(v) Lead nitrate.

Question 5

Salts A, B, C, D and E undergo reactions (i) to (v) respectively. Identify the anion present in these salts on the basis of these reactions.

(a) When silver nitrate solution is added to a solution of A, a white precipitate, insoluble in dilute nitric acid, is formed.

(b) Addition of dilute hydrochloric acid to B produces a gas which turns lead acetate paper black.

(c) When a freshly prepared solution of ferrous sulphate is added to a solution of C and concentrated sulphuric acid is gently poured from the side of the test-tube, a brown ring is formed.

(d) When dilute sulphuric acid is added to D, a gas is produced which turns acidified potassium dichromate solution from orange to green.

(e) Addition of dilute hydrochloric acid to E produces an effervescence. The gas produced turns lime water milky but does not affect acidified potassium dichromate solution.

Exercise 13 Short Answer Type

Answer:

(a) Chloride ion (Cl-)

(b) Sulphide ion (S2-)

(c) Nitrate (NO3-)

(d) Sulphite ion (SO32-)

(e) Carbonate ion (CO32-)

Question 6

State your observations when:

(a) lead nitrate solution and sodium chloride solution are mixed.

(b) zinc chloride solution, zinc nitrate solution and zinc sulphate solutions are added individually to

(i) barium chloride solution,

(ii) lead nitrate solution.

(c) Decomposition of bicarbonates by dil. H2SO4

2NaHCO3 + H2SO4 ⟶ Na2SO4 + 2H2O + 2CO2

2KHCO3 + H2SO4 ⟶ K2SO4 + 2H2O + 2CO2

(d) Zinc carbonate is heated strongly.

(e) a piece of moist blue litmus paper is introduced in a jar of chlorine.

(f) paper soaked in potassium permanganate solution — is introduced in each case into a jar of sulphur dioxide.

(g) When moist starch iodide paper is introduced into chlorine gas.

Exercise 13 Short Answer Type

Answer:

(a) When lead nitrate solution is mixed with sodium chloride solution, a white precipitate of lead chloride is seen and the soluble salt sodium nitrate is formed.

2NaCl + Pb(NO3)2 ⟶ 2Na(NO3)2 + PbCl2

Precipitate of lead chloride and sodium nitrate are formed.

(b)

    Zinc Chloride SolutionZinc Nitrate SolutionZinc Sulphate Solution
Barium Chloride SolutionNo reactionNo ppt. observedWhite ppt. is obtained which is insoluble in mineral acid.
Lead Nitrate SolutionWhite ppt. is obtainedNo reactionNo ppt. observed

(c) Carbon dioxide gas is evolved with brisk effervescence which turns blue litmus red and extinguishes a burning wooden splinter.

(d) When zinc carbonate is strongly heated, the light amorphous white solid, changes to pale yellow colour.

ZnCO3 Δ\xrightarrow{\Delta} ZnO + CO2

(e) Moist blue litmus turns red and then may eventually get bleached.

(f) Sulphur dioxide turns potassium permanganate from pink to clear colourless.

2KMnO4 + 2H2O + 5SO2 ⟶ K2SO4 + 2MnSO4 + 2H2SO4

(g) Chlorine gas turns moist starch iodide paper blue black.

Cl2 + 2KI ⟶ 2KCl + I2
[Starch + I2 ⟶ blue black colour]

Question 7

Complete the following table and write your observations.

  Hydrogen sulphideAmmoniaSulphur dioxideHydrogen chloride
Shake the gas with red litmus solution        
Shake the gas with blue litmus solution        
Apply a burning splint to the gas        
Exercise 13 Short Answer Type

Answer:

  Hydrogen sulphideAmmoniaSulphur dioxideHydrogen chloride
Shake the gas with red litmus solutionNo changeRed litmus becomes blueNo changeNo change
Shake the gas with blue litmus solutionBlue litmus becomes redNo changeBlue litmus becomes redBlue litmus becomes red
Apply a burning splint to the gasBurning splint is extinguishedBurning splint is extinguishedBurning splint is extinguishedBurning splint is extinguished

Question 8

Identify the anion present in the following compounds :

(a) Compound X on heating with copper turnings and conc. sulphuric acid liberates a reddish brown gas.

(b) When a solution of compound Y is treated with silver nitrate solution a white precipitate is obtained which is soluble in excess of ammonium hydroxide solution.

(c) Compound Z which on reacting with dilute sulphuric acid liberates a gas which turns lime water milky, but the gas has no effect on acidified potassium dichromate solution.

(d) Compound L on reacting with barium chloride solution gives a white precipitate insoluble in dilute hydrochloric acid or dilute nitric acid.

Exercise 13 Short Answer Type

Answer:

(a) Nitrate ion, NO3-

(b) Chloride ion, Cl-

(c) Carbonate ion, CO32-

(d) Sulphate ion, SO42-

Question 9

State giving reasons if:

(a) zinc and aluminium can be distinguished by heating the metal powder with concentrated sodium hydroxide solution.

(b) calcium nitrate and lead nitrate can be distinguished by adding ammonium hydroxide solution to the salt solution.

Exercise 13 Short Answer Type

Answer:

(a) Zinc and aluminium cannot be distinguished by heating the metal powder with concentrated sodium hydroxide solution as they both react with conc. alkalis to form soluble sodium salts and hydrogen gas.

Zinc reacts to form sodium zincate

Zn + 2NaOH ⟶ H2 + Na2ZnO2 [sodium zincate]

Aluminium reacts to form sodium aluminate

2Al + 2NaOH + 2H2O ⟶ 3H2 + 2NaAlO2 [sodium aluminate]

(b) Yes, calcium nitrate and lead nitrate can be distinguished using ammonium hydroxide solution. Ammonium hydroxide on reaction with lead nitrate gives chalky white precipitate of Pb(OH)2. No precipitation occurs on adding Ammonium hydroxide to calcium nitrate even when it is added in excess.

Pb(NO3)2 + 2NH4OH ⟶ Pb(OH)2 + 2NH4NO3

Question 10

Identify the substance 'R' based on the information given below :

The pale green solid 'R' turns reddish brown on heating. Its aqueous solution gives a white precipitate with barium chloride solution. The precipitate is insoluble in mineral acids.

Exercise 13 Short Answer Type

Answer:

The substance 'R' is Ferrous sulphate (FeSO4.7H2O). When heated strongly, the hydrous pale green ferrous sulphate (FeSO4.7H2O), loses it's water of crystallization and decomposes to form brown ferric oxide Fe2O3 along with sulphur dioxide (SO2) and sulphur trioxide (SO3).

FeSO4.7H2O Δ\xrightarrow{\Delta} FeSO4 + 7H2O

2FeSO4 Δ\xrightarrow{\Delta} Fe2O3 + SO2 + SO3

Ferrous sulphate on reaction with barium chloride soln., forms a white ppt. of barium sulphate (BaSO4) which is insoluble in mineral acids.

Question 11

Write the equation for the reaction of magnesium sulphate solution with barium chloride solution.

Exercise 13 Short Answer Type

Answer:

MgSO4 + BaCl2 ⟶ BaSO4 ↓ [white ppt.] + MgCl2

Exercise 13 Very Short Answer Type

12 questions

Question 1

Match the gases in column I to the identification of the gases mentioned in column II

Column IColumn II
(a) Hydrogen sulphideA. Turns acidified potassium dichromate solution green
(b) Nitric oxideB. turns lime water milky
(c) Carbon dioxideC. Turns reddish brown when it reacts with oxygen
(d) Sulphur dioxideD. Turns moist lead aceate paper silvery black
Exercise 13 Very Short Answer Type

Answer:

Column IColumn II
(a) Hydrogen sulphideD. Turns moist lead aceate paper silvery black
(b) Nitric oxideC. Turns reddish brown when it reacts with oxygen
(c) Carbon dioxideB. Turns lime water milky
(d) Sulphur dioxideA. Turns acidified potassium dichromate solution green

Question 2

Identify the following substances :

(a) An alkaline gas which gives dense white fumes with hydrogen chloride.

(b) The gas has an offensive smell like rotten eggs.

(c) A colourless gas which can be used as a bleaching agent.

Exercise 13 Very Short Answer Type

Answer:

(a) Ammonia

(b) Hydrogen sulphide

(c) Sulphur dioxide

Question 3

Name :

(a) The gas which turns acidified potassium dichromate solution green.

(b) A gas which turns moist lead acetate paper silvery black

Exercise 13 Very Short Answer Type

Answer:

(a) Sulphur dioxide gas (SO2)

(b) Hydrogen sulphide (H2S)

Question 4

From the following list of substances choose those which meet the description given below.

  1. Ammonium chloride
  2. Ammonium nitrate
  3. Chlorine
  4. Dilute hydrochloric acid
  5. Iron
  6. Lead nitrate
  7. Manganese (IV) oxide
  8. Silver nitrate
  9. Sodium nitrate
  10. Sodium nitrite
  11. Sulphur

Two compounds whose aqueous solutions give white precipitates with dilute hydrochloric acid.

Exercise 13 Very Short Answer Type

Answer:

Silver nitrate and Lead nitrate.

HCl + AgNO3 ⟶ AgCl + HNO3
2HCl + Pb(NO3)2 ⟶ PbCl2 + 2HNO3

Question 5

Use the information given in (a) to (h) to identify the substances P to W selecting your answers from the given list.

List    
CalciumOxygenCopper (II) oxide
CarbonCalcium hydroxideCopper (II) nitrate
Lead (II) oxideHydrogen chlorideChlorine
Lead (II) nitrateCalcium oxideAmmonium chloride

(a) P is a white solid. When heated produces white fumes (sublime).

(b) P and R on warming produce an alkaline gas.

(c) On adding water to T, heat is evolved and R is formed.

(d) Q burns brightly in air to form T.

(e) When S is heated, it gives off brown fumes and leaves a black residue of U.

(f) A solution of S is formed by warming U with dilute nitric acid.

(g) V is a gaseous non-metallic element that reacts with hydrogen to form W.

(h) A solution of W will neutralise the solution of R.

Exercise 13 Very Short Answer Type

Answer:

(P) Ammonium chloride

(Q) Calcium

(R) Calcium hydroxide

(S) Lead (II) Nitrate

(T) Calcium Oxide

(U) Lead (II) Oxide

(V) Chlorine

(W) Hydrogen chloride

Question 6

Copy and complete the following table which refers to the action of heat on some carbonates :

CarbonateColour of residue on cooling
Zinc carbonate
Lead carbonate
Copper carbonate
Exercise 13 Very Short Answer Type

Answer:

CarbonateColour of residue on cooling
Zinc carbonateWhite
Lead carbonateYellow
Copper carbonateBlack

Question 7

Sodium hydroxide solution is added first in a small quantity, then in excess to the aqueous salt solutions of copper (II) sulphate, zinc nitrate, lead nitrate, calcium chloride and iron (III) sulphate. Copy the following table and write the colour of the precipitate in (i) to (v) and the nature of the precipitate (soluble or insoluble) in (vi) to (x).

Aqueous salt solutionColour of precipitate when NaOH is added in a small quantityNature of precipitate (soluble or insoluble) when NaOH is added in excess
Copper (II) sulphate(i)(vi)
Zinc nitrate(ii)(vii)
Lead nitrate(iii)(viii)
Calcium chloride(iv)(ix)
Iron (III) sulphate(v)(x)
Exercise 13 Very Short Answer Type

Answer:

Aqueous salt solutionColour of precipitate when NaOH is added in a small quantityNature of precipitate (soluble or insoluble) when NaOH is added in excess
Copper (II) sulphate(i) Pale blue(vi) Insoluble
Zinc nitrate(ii) White gelatinous(vii) Soluble
Lead nitrate(iii) White chalky(viii) Soluble
Calcium chloride(iv) White curdy(ix) Insoluble
Iron (III) sulphate(v) Reddish brown(x) Insoluble

Question 8

Mention the colour changes observed when following indicators are added:

SolutionAcidsAlkalies
(a) Alkaline phenolphthalein solution,  
(b) Methyl orange solution,  
(c) Neutral litmus solution  
Exercise 13 Very Short Answer Type

Answer:

SolutionAcidsAlkalies
(a) Alkaline phenolphthalein solution,ColourlessPink
(b) Methyl orange solutionPinkYellow
(c) Neutral litmus solutionRedBlue

Question 9

(a) Select the correct answer from A, B, C and D.

A. Nitroso iron (II) sulphate

B. Iron (III) chloride

C. Chromium sulphate

D. Lead (II) chloride.

(a) The compound which is responsible for the green colour formed when SO2 is bubbled through acidified potassium dichromate solution.

(b) Compound responsible for brown ring.

Exercise 13 Very Short Answer Type

Answer:

(a) Chromium sulphate

K2Cr2O7 + H2SO4 + 3SO2 ⟶ K2SO4 + Cr2(SO4)3 + H2O

(b) Nitroso iron (II) sulphate

Question 10

Choose from the list of substances — Acetylene gas, aqua fortis, coke, brass, barium chloride, bronze, platinum.

An aqueous salt solution used for testing sulphate radical.

Exercise 13 Very Short Answer Type

Answer:

Barium chloride.

Question 11

Identify :

(a) The flame test with a salt P gave a brick red flame. What is the cation in P.

(b) pH of liquid R is 10. What kind of substance is R ?

Exercise 13 Very Short Answer Type

Answer:

(a) Cation in P is Ca2+ (calcium ion).

(b) R is an alkaline substance.

Question 12

A student was asked to perform two experiments in the laboratory based on the instructions given:

Observe the picture given below and state one observation for each of the Experiments 1 and 2 that you would notice on mixing the given solutions.

(a) Experiment 1

A student was asked to perform two experiments in the laboratory based on the instructions given: ICSE 2025 Chemistry Solved Question Paper.

(b) Experiment 2

A student was asked to perform two experiments in the laboratory based on the instructions given: ICSE 2025 Chemistry Solved Question Paper.
Exercise 13 Very Short Answer Type

Answer:

(a) White precipitate of barium sulphate is formed.
Reason — When a solution of zinc sulphate is added to a solution of barium chloride, a double displacement reaction occurs. This reaction involves the exchange of ions between the two compounds and a white precipitate of barium sulphate is formed.
ZnSO4 (aq) + BaCl2 (aq) ⟶ BaSO4 (s) + ZnCl2 (aq).

(b) Blue precipitate dissolves to form an inky blue/deep blue solution.
Reason — The light blue precipitate of copper(II) hydroxide (Cu(OH)2) dissolves in excess of ammonium hydroxide due to the formation of a deep blue complex, tetraamminecopper(II) ([Cu(NH3)4]2+), making it soluble.

Intext Questions

3 questions

Question 1

(a) Give only one suitable chemical test to identify the following gases.

(i) Ammonia

(ii) Sulphur dioxide

(iii) Hydrogen chloride

(iv) Chlorine

(v) Carbon dioxide

(vi) Oxygen

(vii) Hydrogen

(b) Select a basic gas mentioned in Q. 1(a). How is the basic nature suspected?

(c) Select acidic gases from the gases mentioned in Q. 1 (a). How is the acidic nature suspected?

(d) The two gases A and B are bleaching agents. A is greenish yellow and bleaches due to it's oxidising property while B a colourless gas bleaches due to reduction. Identify A and B.

(e) Which gas turns blue cobalt chloride paper light pink?

Give one similarity in test between (i) Cl2 and HCl (ii) SO2 and CO2.

Intext Questions

Answer:

(i) Ammonia — When a glass rod dipped in conc. HCl is brought near the gas, dense white fumes of ammonium chloride are formed.

(ii) Sulphur dioxide — Sulphur dioxide gas turns acidified potassium permanganate from pink to clear colourless and acidified potassium dichromate from orange to clear green.

(iii) Hydrogen chloride — Forms a curdy white ppt. on passage through AgNO3 solution. The precipitate dissolves in excess of NH4OH.

(iv) Chlorine — Chlorine turns moist blue litmus red and then bleaches it.

(v) Oxygen — Oxygen gas rekindles a glowing wooden splinter.

(iv) Hydrogen — Hydrogen gas burns with a 'pop' sound in air.

(b) Ammonia is a basic gas. It turns red litmus blue.

(c) Sulphur dioxide, Hydrogen chloride, Chlorine, Carbon dioxide.

(d) A is Chlorine and B is Sulphur dioxide.

(e) Water vapour

(i) Similarity in test of Cl2 and HCl — Forms a white ppt. on reaction with AgNO3 solution.

(ii) Similarity in test of SO2 and CO2 — Both turn lime water milky.

Question 2

Name the gases which

(a) extinguishes burning wooden splinter.

(b) turns moist red litmus blue.

(c) do no effect on moist litmus.

(d) affect the acidified K2Cr2O7 paper and also turns lime water dirty milky.

Intext Questions

Answer:

(a) NH3, HCl, SO2, H2S, CO2, NO2, Cl2.

(b) Ammonia [NH3]

(c) Water vapour, hydrogen, oxygen

(d) sulphur dioxide [SO2]

Question 3

Name:

(a) Two carbonates which do not produce carbon dioxide on heating.

(b) A colourless gas which bleaches

(c) Gases which have sour taste

(d) Greenish yellow gas which also bleaches

(e) Gas with rotten egg smell.

Intext Questions

Answer:

(a) Sodium carbonate [Na2CO3] and potassium carbonate [K2CO3]

(b) Sulphur dioxide [SO2]

(c) Carbon dioxide [CO2]

(d) Chlorine [Cl2]

(e) Hydrogen sulphide [H2S]