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ICSE Class 8 Chemistry Question 4 of 18

Hydrogen — Question 9

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Question

Question 9

(a) Name a process by which hydrogen gas is manufactured.

(b) Give equations for the reactions.

(c) How is hydrogen separated from carbon dioxide and carbon monoxide?

Answer

(a) Bosch process

(b) Equations for the reactions of Bosch process are:

Production of water gas:

Chot coke+H2Osteam→1000°C(CO+H2)water gas−Heat\underset{\text{hot coke}}{\text{C}} + \underset{\text{steam}}{\text{H}_2 \text{O}} \xrightarrow {1000\degree\text{C}} \underset{\text{water gas}}{(\text{CO} + \text{H}_2)} - \text{Heat}

Reduction of steam by water gas:

(CO+H2)water gas+H2Osteam→450°CFe2O3/Cr2O3CO2+2H2+Heat\underset{\text{water gas}}{(\text{CO}+\text{H}_2)} + \underset{\text{steam}}{\text{H}_2 \text{O}} \xrightarrow [\text{450\degree C}] {\text{Fe}_2\text{O}_3/ \text{Cr}_2\text{O}_3} \text{CO}_2 + 2\text{H}_2 + \text{Heat}

(c) Hydrogen is separated from carbon dioxide by passing the mixture through water under pressure, where carbon dioxide gets dissolved leaving behind hydrogen. Carbon dioxide can also be separated by passing it through caustic potash (KOH) solution.

2KOH + CO2 ⟶ K2CO3 + H2O

Carbon monoxide is separated by passing through ammoniacal cuprous chloride in which carbon monoxide dissolves leaving behind hydrogen.

CuCl + CO + 2H2O ⟶ CuCl.CO.2H2O