Question

Calculate the volume of air at NTP required for the complete combustion of 1 kg of coal containg 90 % graphite and 5 % hydrogen if the density of air is 1.296 g/liter at NTP. Assuming that air contains 23 % by weight of oxygen.

Answer 1

Answer:

Combustion of carbon may be given as,  

C(s)+O  

2

​  

(g)→CO  

2

​  

(g)  

∴ 12 g carbon requires 1 mole O  

2

​  

 for complete combustion  

∴ 1000 g carbon will require  

12

1

​  

×1000 mole O  

2

​  

 for combustion,  i.e., 83.33 mole O  

2

​  

 

Volume of O  

2

​  

 at NTP=83.33×22.4litre=1866.592litre

∵ 21 litre O  

2

​  

 is present in 100 litre air .  

∴ 1866.592 litre O  

2

​  

 will be present  

21

100

​  

×1866.592litre

O  2

​=8888.5litre=8.8885×10  

3  litre