Q: Question 7Give balanced equations for the following conversions.(a) Sodium zincate from zinc(b) Sodium plumbite from lead(c) Sodium aluminate from aluminium.

(a) Zn+2NaOH⟶Na2ZnO2[sodium zincate]+H2[g]\text{(a) } \text{Zn} + 2\text{NaOH} \longrightarrow \underset{\text{[sodium zincate]}}{\text{Na}_2\text{ZnO}_2} + \text{H}_2 \text{[g]}(a) Zn+2NaOH⟶[sodium zincate]Na2ZnO2+H2[g](b) Pb+2NaOH⟶Na2PbO2[sodium plumbite]+H2[g]\text{(b) } \text{Pb} + 2\text{NaOH} \longrightarrow \underset{\text{[sodium plumbite]}}{\text{Na}_2\text{PbO}_2} + \text{H}_2 \text{[g]}(b) Pb+2NaOH⟶[sodium plumbite]Na2PbO2+H2[g](c) 2Al+2NaOH+2H2O⟶2NaAlO2[sodium aluminate]+H2[g]\text{(c) } 2\text{Al} + 2\text{NaOH} + 2\text{H}_2\text{O}\longrightarrow \underset{\text{[sodium aluminate]}}{2\text{NaAlO}_2} + \text{H}_2 \text{[g]}(c) 2Al+2NaOH+2H2O⟶[sodium aluminate]2NaAlO2+H2[g]

Question 1

Question 4Give balanced equations for obtaining hydrogen from cold water using –(a) A monovalent active metal(b) A divalent active metal

Accepted Answer

(a) Monovalent active metal Na :2Na+2H2Ocold water⟶2NaOH+H22	ext{Na} + \underset{	ext{cold water}}{2	ext{H}_2	ext{O}} \longrightarrow 2	ext{NaOH} + 	ext{H}_22Na+cold water2H2​O​⟶2NaOH+H2​(b) Divalent active metal Ca :Ca+2H2Ocold water⟶Ca(OH)2+H2	ext{Ca} + \underset{	ext{cold water}}{2	ext{H}_2	ext{O}} \longrightarrow 	ext{Ca(OH)}_2 + 	ext{H}_2Ca+cold water2H2​O​⟶Ca(OH)2​+H2​

Question 2

Question 7Give balanced equations for the following conversions.(a) Sodium zincate from zinc(b) Sodium plumbite from lead(c) Sodium aluminate from aluminium.

Accepted Answer

(a) Zn+2NaOH⟶Na2ZnO2[sodium zincate]+H2[g]	ext{(a) } 	ext{Zn} + 2	ext{NaOH} \longrightarrow \underset{	ext{[sodium zincate]}}{	ext{Na}_2	ext{ZnO}_2} + 	ext{H}_2 	ext{[g]}(a) Zn+2NaOH⟶[sodium zincate]Na2​ZnO2​​+H2​[g](b) Pb+2NaOH⟶Na2PbO2[sodium plumbite]+H2[g]	ext{(b) } 	ext{Pb} + 2	ext{NaOH} \longrightarrow \underset{	ext{[sodium plumbite]}}{	ext{Na}_2	ext{PbO}_2} + 	ext{H}_2 	ext{[g]}(b) Pb+2NaOH⟶[sodium plumbite]Na2​PbO2​​+H2​[g](c) 2Al+2NaOH+2H2O⟶2NaAlO2[sodium aluminate]+H2[g]	ext{(c) } 2	ext{Al} + 2	ext{NaOH} + 2	ext{H}_2	ext{O}\longrightarrow \underset{	ext{[sodium aluminate]}}{2	ext{NaAlO}_2} + 	ext{H}_2 	ext{[g]}(c) 2Al+2NaOH+2H2​O⟶[sodium aluminate]2NaAlO2​​+H2​[g]

Question 3

Question 10State the conditions and give balanced equations for the conversion of –(a) coke to water gas,(b) water gas to hydrogenin the Bosch process.

Accepted Answer

(a) coke to water gasCcoke+H2Osteam→1000°C[CO+H2]water gas−Δ\underset{	ext{coke}}{	ext{C}} + \underset{	ext{steam}}{	ext{H}_2	ext{O}} \xrightarrow{1000 \degree 	ext{C}} \underset{	ext{water gas}}{[	ext{CO} + 	ext{H}_2 ]} - \DeltacokeC​+steamH2​O​1000°C​water gas[CO+H2​]​−Δ(b) water gas to hydrogen[CO+H2]water gas+H2Oexcess steam→450°CFe2O3 CO2+2H2+Δ\underset{	ext{water gas}}{[	ext{CO} + 	ext{H}_2 ]} + \underset{	ext{excess steam}}{	ext{H}_2	ext{O}} \underset{	ext{Fe}_2	ext{O}_3} {\xrightarrow{450 \degree 	ext{C}}} 	ext{ CO}_2 + 2	ext{H}_2 + \Deltawater gas[CO+H2​]​+excess steamH2​O​Fe2​O3​450°C​​ CO2​+2H2​+Δ

Question 4

Question 1Preparation of hydrogen[General Methods]  Reactions of active metals - cold water  1. PotassiumK + H2O ⟶ ............... + ............... [g]2. SodiumNa + H2O ⟶ ............... + ............... [g]3. CalciumCa + H2O ⟶ ............... + ............... [g]Reaction of metals with steam  4. MagnesiumMg + H2O ⟶ ............... + ............... [g]5. AluminiumAl + H2O ⟶ ............... + ............... [g]6. ZincZn + H2O ⟶ ............... + ............... [g]7. IronFe + H2O ⇌ ............... + ............... [g]Reactions of metals with dilute acids  8. MagnesiumMg + HCl ⟶ ............... + ............... [g]9. AluminiumAl + H2SO4 ⟶ ............... + ............... [g]10. ZincZn + HCl ⟶ ............... + ............... [g]11. IronFe + HCl ⟶ ............... + ............... [g]Reactions of metals - alkali [conc. soln.]  12. ZincZn + NaOH ⟶ ............... + ............... [g]Zn + KOH ⟶ ............... + ............... [g]13. LeadPb + NaOH ⟶ ............... + ............... [g]14. AluminiumAl + NaOH + H2O ⟶ ............... + ............... [g]Al + KOH + H2O ⟶ ............... + ............... [g]

Accepted Answer

Preparation of hydrogen[General Methods]  Reactions of active metals - cold water  1. Potassium2K + 2H2O ⟶ 2KOH + H2 [g]2. Sodium2Na + 2H2O ⟶ 2NaOH + H2 [g]3. CalciumCa + 2H2O ⟶ Ca(OH)2 + H2 [g]Reaction of metals with steam  4. MagnesiumMg + H2O ⟶ MgO + H2 [g]5. Aluminium2Al + 3H2O ⟶ Al2O3 + 3H2 [g]6. ZincZn + H2O ⟶ ZnO + H2 [g]7. Iron3Fe + 4H2O ⇌ Fe3O4 + 4H2 [g]Reactions of metals with dilute acids  8. MagnesiumMg + 2HCl⟶ MgCl2 + H2 [g]9. Aluminium2Al + 3H2SO4 ⟶ Al2(SO4)3 + 3H2 [g]10. ZincZn + H2SO4 ⟶ ZnSO4 + H2 [g]11. IronFe + 2HCl ⟶ FeCl2 + H2 [g]Reactions of metals - alkali [conc. soln.]  12. ZincZn + 2NaOH ⟶ Na2ZnO2 + H2 [g]Zn + 2KOH ⟶ K2ZnO2 + H2 [g]13. LeadPb + 2NaOH ⟶ Na2PbO2 + H2 [g]14. Aluminium2Al+ 2NaOH + 2H2O ⟶ 2NaAlO2 + 3H2 [g]2Al + 2KOH + 2H2O ⟶ 2KAlO2 + 3H2 [g]

Question 5

Question 8Hydrogen is manufactured by 'Bosch Process'.(a) Give the equations with conditions.(b) How can you obtain hydrogen from a mixture of Hydrogen and carbon monoxide?

Accepted Answer

(a) Steam is passed over hot coke (1000°C) in furnaces of a special design, called converters, giving water gas.Chot coke+H2Osteam→1000°C[CO+H2]water gas−Δ\underset{	ext{hot coke}}{	ext{C}} + \underset{	ext{steam}}{	ext{H}_2	ext{O}} \xrightarrow{1000 \degree 	ext{C}} \underset{	ext{water gas}}{[	ext{CO} + 	ext{H}_2 ]} - \Deltahot cokeC​+steamH2​O​1000°C​water gas[CO+H2​]​−ΔThe reaction is endothermic.(b) Water gas i.e., hydrogen and carbon monoxide is mixed with excess steam and passed over heated ferric oxide, which acts as a catalyst and chromic oxide Cr2O3 which acts as a promoter.[CO+H2]water gas+H2Osteam→450°CFe2O3CO2+2H2+Δ\underset{	ext{water gas}}{[	ext{CO} + 	ext{H}_2 ]} + \underset{	ext{steam}}{	ext{H}_2	ext{O}} \xrightarrow[450 \degree 	ext{C}]{	ext{Fe}_2	ext{O}_3} 	ext{CO}_2 + 2	ext{H}_2 + \Deltawater gas[CO+H2​]​+steamH2​O​Fe2​O3​450°C​CO2​+2H2​+Δ

Question 6

Question 8Steam can react with a metal and a non-metal to liberate hydrogen. Give the necessary conditions and equations for the same.

Accepted Answer

The conditions necessary for the reaction of steam with a metal and a non-metal to liberate hydrogen are:Presence of steam — Steam (water vapor) is required for this reaction to occur.Heat — The reaction is typically carried out at high temperatures to facilitate the reaction between the metal or non-metal and steam.Reaction of Zinc (metal) with steam to liberate hydrogen:Znheated+H2Osteam⟶ZnO+H2↑\underset{	ext{heated}}{	ext{Zn}} + \underset{	ext{steam}}{	ext{H}_2	ext{O}} \longrightarrow 	ext{ZnO} + 	ext{H}_2 \uparrowheatedZn​+steamH2​O​⟶ZnO+H2​↑Reaction of Carbon (non-metal) with steam to liberate hydrogen:CRed Hot Coke+H2Osteam⟶CO+H2⏟Water gas\underset{	ext{Red Hot Coke}}{	ext{C}} + \underset{	ext{steam}}{	ext{H}_2	ext{O}} \longrightarrow \underbrace{	ext{CO} + 	ext{H}_2}_{	ext{Water gas}}Red Hot CokeC​+steamH2​O​⟶Water gasCO+H2​​​

Question 7

Question 9Hydrogen is obtained by displacement from(a) dilute sulphuric acid(b) dilute hydrochloric acidWrite equations using zinc and iron.Why does not copper show similar behaviour?

Accepted Answer

(a) dilute sulphuric acidZn + H2SO4 (dil.) ⟶ ZnSO4 + H2 ↑Fe + H2SO4 (dil.) ⟶ FeSO4 + H2 ↑(b) dilute hydrochloric acidZn + 2HCl (dil.) ⟶ ZnCl2 + H2 ↑Fe + 2HCl (dil.) ⟶ FeCl2 + H2 ↑Zinc and iron are above hydrogen in activity series of metals whereas copper is below hydrogen in the series. As metals below hydrogen cannot displace it from dilute acids hence, copper does not show similar behaviour as zinc and iron.

Question 8

Question 12Complete and balance the following equations.(a) Na + H2O ⟶ ............... + ...............(b) Ca + H2O ⟶ ............... + ...............(c) Mg + H2O ⟶ ............... + ...............(d) Zn + H2O ⟶ ............... + ...............(e) Fe + H2O ⟶ ............... + ...............(f) Zn + HCl ⟶ ............... + ...............(g) Al + H2SO4 ⟶ ............... + ...............(h) Fe + HCl ⟶ ............... + ...............(i) Zn + NaOH ⟶ ............... + ...............(j) Al + KOH + H2O ⟶ ............... + ...............

Accepted Answer

(a) 2Na + 2H2O ⟶ 2NaOH + H2(b) Ca + 2H2O ⟶ Ca(OH)2 + H2(c) Mg + 2H2O ⟶ Mg(OH)2 + H2(d) Zn + H2O ⟶ ZnO + H2(e) 3Fe + 4H2O ⇌ Fe3O4 + 4H2(f) Zn + 2HCl ⟶ ZnCl2 + H2(g) 2Al + 3H2SO4 ⟶ Al2(SO4)3 + 3H2(h) Fe + 2HCl ⟶ FeCl2 + H2(i) Zn + 2NaOH ⟶ Na2ZnO2 + H2(j) 2Al + 2KOH + 2H2O ⟶ 2KAlO2 + 3H2

Question 9

Question 16Under what conditions can hydrogen be made to combine with(a) nitrogen(b) chlorine(c) sulphur(d) oxygenName the products in each case and write the equation for each reaction.

Accepted Answer

(a) Three volumes of hydrogen and one volume of nitrogen react at temperature 450-500°C, pressure 200-900 atm in the presence of a catalyst, finely divided iron, with molybdenum as a promoter to give ammonia.N2+3H2⇌450-500 °CFe2NH3+Δ	ext{N}_2 + 3	ext{H}_2 \xrightleftharpoons[	ext{450-500 \degree C}]{	ext{Fe}} 	ext{2NH}_3 + \DeltaN2​+3H2​Fe450-500 °C​2NH3​+Δ(b) Equal volumes of hydrogen and chlorine react slowly in diffused sunlight but explosively in direct sunlight, to form hydrogen chloride.H2+Cl2→sunlight2HCl	ext{H}_2 + 	ext{Cl}_2 \xrightarrow{	ext{sunlight}} 2	ext{HCl}H2​+Cl2​sunlight​2HCl(c) Hydrogen gas on passing through molten sulphur reacts to give hydrogen sulphide.H2+Smolten sulphur⟶H2S	ext{H}_2 + \underset{	ext{molten sulphur}}{	ext{S}} \longrightarrow 	ext{H}_2	ext{S}H2​+molten sulphurS​⟶H2​S(d) Hydrogen burns (in presence of electric spark) with a 'pop' sound in oxygen and with a blue flame forming water.2H2+O2→electric spark2H2O2	ext{H}_2 + 	ext{O}_2 \xrightarrow{	ext{electric spark}} 2	ext{H}_2	ext{O}2H2​+O2​electric spark​2H2​O

Question 10

Question 17When hydrogen is passed over a black solid compound A, the products are 'a colourless liquid' and 'a reddish-brown metal B.'Substance B is divided into two parts, each placed in separate test tubes.Dilute HCl is added to one part of substance B and dilute HNO3 to the other.(a) Name the substances A and B.(b) Give two tests for the colourless liquid formed in the experiment.(c) What happens to substance A when it reacts with hydrogen ? Give reasons for your answer.(d) Write an equation for the reaction between hydrogen and substance A.(e) Is there any reaction between substance B and dilute hydrochloric acid ? Give reasons for your answer.

Accepted Answer

(a) A = copper oxide [CuO],B = copper [Cu](b) The liquid does not change the colour of blue or red litmus paper, showing neutral nature.It changes the colour of cobalt chloride paper from blue to pink colour. Hence, the liquid produced is water.(c) Black copper oxide (A) is reduced to copper, by losing oxygen. This happens because, hydrogen, the reducing agent reduces copper oxide to copper.(d) CuO + H2 →Δ\xrightarrow{\Delta}Δ​ Cu + H2O(e) As copper is less reactive than hydrogen and lies below it in the metal reactivity series, hence it cannot displace it from HCl. Hence, there is no reaction between them.Cu + HCl ⟶ No reaction

Question 11

Question 3State the similarities of hydrogen with group 1 elements and group 17 elements.

Accepted Answer

Similarity of hydrogen with group 1 elements:Electronic configuration — Both hydrogen and alkali metals have only one electron in their outermost orbits.Ion formation — Both form a cation by loss of an electron.H ⟶ H+ + e-Na ⟶ Na+ + e-Valency — Both have the valency 1.Reducing power — Both act as reducing agents.CuO + H2 ⟶ Cu + H2OCuO + 2Na ⟶ Cu + Na2OReaction with Oxygen — Both react with oxygen to form respective oxides.Hydrogen forms H2OSodium forms Na2OSimilarity of hydrogen with group 17 elements:Electronic configuration — Hydrogen and halogens have one electron less than the nearest inert gas.Physical state — Like halogens (fluorine and chlorine), hydrogen too is a gas.Ion formation — Both form an anion by accepting an electron.H + e- ⟶ H-Cl + e- ⟶ Cl-Valency — Both have the valency 1.Atomicity — Hydrogen as well as halogens exist in the form of diatomic molecules (H2, F2, Cl2, Br2, I2).

Question 12

Question 6How is hydrogen manufactured? Describe with the equation(s) involved.

Accepted Answer

Hydrogen is manufactured by Bosch process. It consists of following steps:1. Production of water gasCcoke+H2Osteam→1000°C[CO+H2]water gas−Δ\underset{	ext{coke}}{	ext{C}} + \underset{	ext{steam}}{	ext{H}_2	ext{O}} \xrightarrow{1000 \degree 	ext{C}} \underset{	ext{water gas}}{[	ext{CO} + 	ext{H}_2 ]} - \DeltacokeC​+steamH2​O​1000°C​water gas[CO+H2​]​−ΔReactants : White hot coke and steamTemperature : Around 1000°CProcess : Passage of steam over white hot coke [carbon]Chamber : Specially designed convertor2. Reduction of steam to hydrogen by carbon monoxide[CO+H2]water gas+H2Oexcess steam→450°CFe2O3 CO2+2H2+Δ\underset{	ext{water gas}}{[	ext{CO} + 	ext{H}_2 ]} + \underset{	ext{excess steam}}{	ext{H}_2	ext{O}} \underset{	ext{Fe}_2	ext{O}_3} {\xrightarrow{450 \degree 	ext{C}}} 	ext{ CO}_2 + 2	ext{H}_2 + \Deltawater gas[CO+H2​]​+excess steamH2​O​Fe2​O3​450°C​​ CO2​+2H2​+ΔReactants : Water gas and excess steamTemperature : Around 450°CCatalysts : Iron [III] oxide [Fe2O3], promoter chromic oxide [Cr2O3]Process : Excess steam is mixed with water gas, passed over a catalyst at elevated temperatures.[CO is converted to CO2 with a further yield of hydrogen.]3. Separation of carbon dioxide [CO2] and carbon monoxide from the above mixture(a) CO2 is removed by dissolving mixture in water under pressure [30 atmospheres], or caustic potash solution to dissolve CO2.2KOH + CO2 ⟶ K2CO3 + H2O(b) CO is removed by dissolving mixture in ammoniacal cuprous chloride solution.CuCl + CO + 2H2O ⟶ CuCl.CO.2H2O.Thus, hydrogen gas is left behind.

Question 13

Question 2(iv)Assertion (A): In Bosch process, hydrogen and carbon dioxide are formed.Reason (R): Hydrogen and carbon dioxide are separated by passing through ammoniacal cuprous chloride solution.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

A is true but R is false.Explanation — In the second step of Bosch process, water gas is mixed with excess steam and passed over heated ferric oxide, which acts as a catalyst and chromic oxide Cr2O3, which acts as a promoter to produce hydrogen and carbon dioxide.[CO+H2]water gas+H2Oexcess steam→450°CFe2O3 CO2+2H2+Δ\underset{	ext{water gas}}{[	ext{CO} + 	ext{H}_2 ]} + \underset{	ext{excess steam}}{	ext{H}_2	ext{O}} \underset{	ext{Fe}_2	ext{O}_3} {\xrightarrow{450 \degree 	ext{C}}} 	ext{ CO}_2 + 2	ext{H}_2 + \Deltawater gas[CO+H2​]​+excess steamH2​O​Fe2​O3​450°C​​ CO2​+2H2​+ΔHence assertion (A) is true.The mixture Hydrogen and carbon dioxide(CO2 + H2) are separated through caustic potash solution, which removes carbon dioxide by reacting with it, leaving hydrogen. Hence reason (R) is false.

Question 14

Question 2(vii)Assertion (A): Both dilute sulphuric acid and dilute hydrochloric acid displace hydrogen when they react with metals above hydrogen in the activity series.Reason (R): The more reactive element displaces the less reactive element from its salt solution.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both A and R are true and R is the correct explanation of A.Explanation — Metals which are more reactive than hydrogen, when reacted with both dilute sulphuric acid and dilute hydrochloric acid displace hydrogen. The extent to which these reaction occur for a given metal is also based on the activity series of metal where the more reactive element displaces the less reactive element from its salt solution. Hence both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Question 15

Question 2(ix)Assertion (A): Zinc is preferred for the laboratory preparation of hydrogen.Reason (R): Zinc is unique in nature and does not contain any impurity.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

A is true but R is false.Explanation — Zinc granules are preferred for laboratory preparation of hydrogen over pure zinc because the impurity present in granulated zinc is copper, whose catalysing effect speeds up the rate of reaction. Hence the assertion (A) is true.Zinc is unique in nature and does contain impurity like copper. Hence reason (R) is false.

Question 16

Question 2(x)Assertion (A): Reduction is defined as the process of removal of oxygen from a substance or the addition of hydrogen to a substance.Reason (R): Hydrogen is a reducing as well as an oxidising agent.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

A is true but R is false.Explanation — Reduction is also defined as the process that involves removal of oxygen from a substance or the addition of hydrogen to a substance. Hence, the assertion (A) is true.Hydrogen is a reducing agent not oxidising agent. Hence, the reason (R) is false.

Question 17

Question 5(1984)How can you obtain hydrogen from sodium hydroxide [not by electrolysis].

Accepted Answer

When powdered zinc reacts with sodium hydroxide it produces hydrogen.Zn+2NaOH⟶Na2ZnO2sodium zincate+H2[g]	ext{Zn} + 2	ext{NaOH} \longrightarrow \underset{	ext{sodium zincate}}{	ext{Na}_2	ext{ZnO}_2} + 	ext{H}_2 	ext{[g]}Zn+2NaOH⟶sodium zincateNa2​ZnO2​​+H2​[g]

Question 18

Question 2(1988)Explain briefly how hydrogen is manufactured on a large scale, from steam.

Accepted Answer

Step IReaction : Production of water gasCcoke+H2Osteam→1000°C[CO+H2]water gas−Δ\underset{	ext{coke}}{	ext{C}} + \underset{	ext{steam}}{	ext{H}_2	ext{O}} \xrightarrow{1000 \degree 	ext{C}} \underset{	ext{water gas}}{[	ext{CO} + 	ext{H}_2 ]} - \DeltacokeC​+steamH2​O​1000°C​water gas[CO+H2​]​−ΔReactants : White hot coke and steamTemperature : Around 1000°CProcess : Passage of steam over white hot coke [carbon]Chamber : Specially designed convertorStep IIReaction : Reduction of steam to hydrogen by carbon monoxide[CO+H2]water gas+H2Oexcess steam→450°CFe2O3 CO2+2H2+Δ\underset{	ext{water gas}}{[	ext{CO} + 	ext{H}_2 ]} + \underset{	ext{excess steam}}{	ext{H}_2	ext{O}} \underset{	ext{Fe}_2	ext{O}_3} {\xrightarrow{450 \degree 	ext{C}}} 	ext{ CO}_2 + 2	ext{H}_2 + \Deltawater gas[CO+H2​]​+excess steamH2​O​Fe2​O3​450°C​​ CO2​+2H2​+ΔReactants : Water gas and excess steamTemperature : Around 450°CCatalysts : Iron [III] oxide [Fe2O3], promoter chromic oxide [Cr2O3]Process : Excess steam is mixed with water gas, passed over a catalyst at elevated temperatures.[CO is converted to CO2 with a further yield of hydrogen.]Step IIIReaction : Separation of carbon dioxide [CO2] and carbon monoxide from the above mixture(a) CO2 is removed by dissolving mixture in water under pressure [30 atmospheres], or caustic potash solution to dissolve CO2.2KOH + CO2 ⟶ K2CO3 + H2O(b) CO is removed by dissolving mixture in ammoniacal cuprous chloride solution.CuCl + CO + 2H2O ⟶ CuCl.CO.2H2O.Thus, hydrogen gas is left over.

Question 19

Question 1(1989)State the products of the reaction 'when steam is passed over red-hot iron'.

Accepted Answer

When steam is passed over red hot iron, magnetic oxide of iron and hydrogen are produced.3Fe+4H2Osteam⇌Fe3O4magnetic oxide of iron+4H2hydrogen3	ext{Fe} + \underset{	ext{steam}}{4	ext{H}_2	ext{O}} ightleftharpoons \underset{	ext{magnetic oxide of iron}}{	ext{Fe}_3	ext{O}_4} + \underset{	ext{hydrogen}}{4	ext{H}_2}3Fe+steam4H2​O​⇌magnetic oxide of ironFe3​O4​​+hydrogen4H2​​

Question 20

Question 1(1991)How would you obtain 'hydrogen from sodium hydroxide' solution other than by electrolysis ?

Accepted Answer

When powdered zinc reacts with sodium hydroxide it produces hydrogen.Zn+2NaOH⟶Na2ZnO2Sodium zincate+H2[g]	ext{Zn} + 2	ext{NaOH} \longrightarrow \underset{	ext{Sodium zincate}}{	ext{Na}_2	ext{ZnO}_2} + 	ext{H}_2 	ext{[g]}Zn+2NaOH⟶Sodium zincateNa2​ZnO2​​+H2​[g]

Study of the First Element — Hydrogen

Additional Questions

Equation Worksheet

Exercise 6B

Exercise 6C

Exercise 6D Descriptive Type

Exercise 6D Multiple Choice Type

Questions

Unit Test Paper 6 — Hydrogen