. The heat evolved in combustion if 112 litres of water gas


water gas

(A) 241.8 kJ

(B) 296.5 kJ

(C) 1312 kJ

(D) 1586 kJ

Best Answer

Correct Answer is (C) 

Explanation:

Molecular formula of water gas =H2 + CO

Combustion of H2-

H2 + 1/2 O2 ⟶ H2O;ΔH=−241.3KJ

Combustion of CO-

CO + 1/2 O2 ⟶ CO2;ΔH=−283KJ

1 mole of H2 and CO each gives,

ΔH=−283 + (−241.8) = −524.8KJ

1 mole of H2 =22.4L

Similarly,

1 mole of CO=22.4L

∴ Total volume  = 22.4 + 22.4 = 44.8L

Therefore,Heat evolved during combustion of 44.8L of water gas =−524.8KJ

Heat evolved during combustion of 112L of water gas = 524.8×112/44.8 = 1312KJ

Hence,the heat evolved during the combustion of 112 litre of water gas at STP is 1312KJ.

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