If LPG cylinder contains mixture of butane and isobutane then the amount of oxygen

If LPG cylinder contains mixture of butane and isobutane then the amount of oxygen that would be required for combustion of 1 kg of it will be :

a) 1.8 kg
b) 3.58 kg
c) 2.7 kg
d) 4.5 kg

The correct answer is b) 3.58 kg.

Solution :

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