Question 1

Question 1(ii)Hydrogen chloride gas is not collected over water, as:It is highly soluble in water.It is less soluble in water.It is lighter than air.It is heavier than air.

Accepted Answer

It is highly soluble in waterReason — Hydrogen chloride gas is not collected over water since it is highly soluble in water.

Question 2

Question 1(v)The gas formed, when calcium bisulphite reacts with dilute HNO3:Sulphur trioxideHydrogenSulphur dioxideHydrogen sulphide

Accepted Answer

Sulphur dioxideReason — Ca(HSO3)2 + 2HNO3 [dil.] ⟶ Ca(NO3)2 + 2H2O + 2SO2

Question 3

Question 1(vi)The IUPAC name of formic acid:Propanoic acidMethanoic acidEthanoic acidButanoic acid

Accepted Answer

Methanoic acidReason — The IUPAC name of formic acid [HCOOH] is methanoic acid.

Question 4

Question 1(viii)Vanadium pentoxide is used as a catalyst in the preparation of:Nitrogen gasNitrogen dioxide gasSulphur trioxide gasCarbon dioxide gas

Accepted Answer

Sulphur trioxide gasReason — Vanadium pentoxide is used during contact process for the preparation of sulphur trioxide gas.2SO2+O2⇌450−500°C /1−2 atmosV2O52SO3+45 K cals2	ext{SO}_2 + 	ext{O}_2 \xrightleftharpoons [450-500	ext{\degree C }/1 - 2 	ext{ atmos}]{	ext{V}_2	ext{O}_5} 2	ext{SO}_3 + 	ext{45 K cals}2SO2​+O2​V2​O5​450−500°C /1−2 atmos​2SO3​+45 K cals

Question 5

Question 1(ix)The catalyst used for the conversion of ethene to ethane:IronNickelCobaltMolybdenum

Accepted Answer

NickelReason — The catalyst used for conversion of ethene to ethane is commonly nickel.C2H4 ethene+H2→300°CNickleC2H6ethane\underset{	ext{ ethene}}{	ext{C}_2	ext{H}_4} + 	ext{H}_2 \xrightarrow[300\degree	ext{C}]{	ext{Nickle}} \underset{	ext{ethane}}{	ext{C}_2	ext{H}_6} etheneC2​H4​​+H2​Nickle300°C​ethaneC2​H6​​

Question 6

Question 1(x)Substance which helps to lower the fusion point of the mixture in Hall Heroult Process:CokeConcentrated sodium hydroxideFluorsparConcentrated potassium hydroxide

Accepted Answer

FluorsparReason — Fluorspar lowers the fusion point of the mixture in Hall Heroult Process and the mixture fuses at 950° C instead of 2050° C.

Question 7

Question 2(i)Define:(a) Isomerism(b) Ores

Accepted Answer

(a) Isomerism — Isomerism is the phenomenon due to which two or more compounds have the same molecular formula but differ in molecular arrangement or in structural formula.(b) Ores — Ores are minerals from which metals are extracted commercially at a comparatively lower cost and with minimum effort.

Question 8

Question 2(iii)Draw the structural diagram of:(a) pentanal(b) propanol(c) 2-butene

Accepted Answer

(a) pentanal(b) propanol(c) 2-butene

Question 9

Question 2(iv)Complete and balance the following chemical equations:(a) H2C = CH2 + Cl2 ⟶(b) C2H6 + O2 [excess] ⟶(c) CH4 + O2 [excess] ⟶

Accepted Answer

(a) H2C = CH2 + Cl2 ⟶ CH2Cl – CH2Cl(b) 2C2H6 + 7O2 [excess] ⟶ 4CO2 + 6H2O(c) CH4 + 2O2 [excess] ⟶ CO2 + 2H2O

Question 10

Question 3(iii)State the observation for the following:(a) Dry ammonia gas reacts with oxygen in the presence of a catalyst.(b) Excess chlorine gas reacts with ammonia gas.(c) Carbon reacts with hot concentrated nitric acid.

Accepted Answer

(a) Dry ammonia gas reacts with oxygen in the presence of platinum (catalyst) to produce nitric oxide (NO), water and heat. Nitric oxide (NO) produced is oxidised to nitrogen dioxide (NO2) and reddish brown vapours are seen in the flask. As the reaction is exothermic, so the platinum (catalyst) continues to glow even after the heating is discontinued.4NH3 + 5O2 →800°CPt.\xrightarrow[800 \degree 	ext{C}]{	ext{Pt.}}Pt.800°C​ 6H2O + 4NO↑ + Δ2NO + O2 ⟶ 2NO2(b) Colourless ammonia gas reacts with greenish yellow chlorine gas in excess producing hydrogen chloride and a yellow explosive liquid (nitrogen trichloride).NH3 + 3Cl2 [excess] ⟶ 3HCl + NCl3(c) Carbon reacts with hot concentrated nitric acid producing carbon dioxide, water and reddish brown fumes of nitrogen dioxide are evolved.C + 4HNO3 ⟶ CO2 + 2H2O + 4NO2

Question 11

Question 4(iii)Complete the table given below which refers to the Laboratory preparation of Ammonia gas:Laboratory preparationReactants usedProducts formedDrying agentMethod of collectionAmmonia gas(a) ...............Calcium chloride + water + ammonia(b) ...............(c) ...............

Accepted Answer

Laboratory preparationReactants usedProducts formedDrying agentMethod of collectionAmmonia gas(a) ammonium chloride [NH4Cl] and calcium hydroxide [Ca(OH)2)]Calcium chloride + water + ammonia(b) quicklime [CaO](c) downward displacement of air

Question 12

Question 4(iv)Identify the terms for the following:(a) The process used to purify Alumina by electrolytic reduction.(b) The experiment used to demonstrate the high solubility of HCl gas.(c) The chemical property of sulphuric acid to form two types of salts with an alkali.

Accepted Answer

(a) Hall-Heroult's process(b) Fountain experiment(c) Dibasic property of sulphuric acid.

Question 13

Question 5(i)Write the balanced chemical equation for the following:(a) Action of heat on manganese dioxide and concentrated hydrochloric acid.(b) Zinc reacts with dilute hydrochloric acid to form zinc chloride.

Accepted Answer

(a) MnO2 + 4HCl ⟶ MnCl2 + 2H2O + Cl2↑(b) Zn + 2HCl ⟶ ZnCl2 + H2↑

Question 14

Question 5(ii)Select the right answer from the brackets and complete the statements:In electrolysis of fused Alumina, the anode is made of (a) ............... [gas carbon/graphite] and the product formed at cathode is (b) ............... [oxygen/aluminium].

Accepted Answer

In electrolysis of fused Alumina, the anode is made of (a) graphite and the product formed at cathode is (b) aluminium

Question 15

Question 5(iii)Give the IUPAC name for the following:

Accepted Answer

(a) Ethene(b) Propanaldehyde(c) 3-methyl Pentane

Question 16

Question 5(iv)Study the diagram, which shows the Brown Ring Test and answer the questions given below:(a) Which ion is determined by Brown Ring Test?(b) Why is freshly prepared iron[II] sulphate used in the test?(c) Name the substance Z.

Accepted Answer

(a) Nitrate ion [NO31-](b) As iron [II] sulphate on exposure to the atmosphere is oxidised to iron [III] sulphate and the test will not answer with iron [III] sulphate, hence, freshly prepared iron[II] sulphate used in the test.(c) Concentrated Sulphuric Acid.

Question 17

Question 6(i)Distinguish between the following as directed:(a) Sodium sulphite solution and sodium sulphate solution. [using dilute H2SO4](b) Lead salt solution and zinc salt solution. [using NH4OH solution in excess]

Accepted Answer

(a) On adding dilute sulphuric acid to sodium sulphite solution and warming, a colourless gas with suffocating smell of burning sulphur is evolved. The evolved gas turns lime water milky and changes the colour of acidified K2Cr2O7 solution from orange to green suggesting that it is SO2.Na2SO3 + H2SO4 (dil.) ⟶ Na2SO4 + H2O + SO2↑Sodium sulphate does not react with dilute sulphuric acid as an acid does not react with its own salt due to the presence of same anion.(b) A lead salt gives a chalky white ppt. on reaction with ammonium hydroxide that is insoluble in excess of ammonium hydroxide. For example:Pb(NO3)2 + 2NH4OH ⟶ 2NH4NO3 + Pb(OH)2 ↓On the other hand, zinc salt forms a white gelatinous ppt. which dissolves when excess of ammonium hydroxide is added. Hence, the two can be distinguished.ZnSO4 + 2NH4OH ⟶ (NH4)2SO4 + Zn(OH)2 ↓Zn(OH)2 + (NH4)2SO4 + 2NH4OH ⟶ [Zn(NH3)4]SO4 + 4H2O

Question 18

Question 6(ii)Give one word for the following statements:(a) The compounds of various metals found in nature with earthly impurities.(b) A homogeneous mixture of two or more metals or a metal and a non-metal in specific ratios.

Accepted Answer

(a) Minerals(b) Alloys

Question 19

Question 6(iii)Identify the acid in each case:(a) The acid formed when sulphur reacts with concentrated nitric acid.(b) An acid, which on adding to lead nitrate solution produces a white precipitate which is soluble on heating.(c) The acid formed when potassium nitrate reacts with a least volatile acid.

Accepted Answer

(a) Sulphuric acid.(b) Hydrochloric acid(c) Nitric acid

Question 20

Question 6(iv)Match column A with column B:Name (A)Functional group (B)1. Aldehyde(a) —OH2. Carboxylic acids(b) —CHO3. Alcohol(c) —COOH

Accepted Answer

Name (A)Functional group (B)1. Aldehyde(b) —CHO2. Carboxylic acids(c) —COOH3. Alcohol(a) —OH

Solved 2022 Semester 2 Question Paper ICSE Class 10 Chemistry

Section A 10 Marks

Section B 30 Marks