Question

C(s)+O2(g)→CO2(g)+400 kJ
C(s)+$\frac{1}{2}$ O2(g)→CO(s)+100 kJ
When coal of purity 60% is allowed to burn in presence of insufficient oxygen, 60% of carbon is converted into ‘CO’ and the remaining is converted into ‘CO2’. The heat generated when 0.6 kg of coal is burnt is _______.

• A. 1600 kJ
• B. 3200 kJ
• C. 4400 kJ
• D. 6600 kJ

Answer 1

Answer: (D)

6600 kJ

Answer 2

Weight of coal = 0.6 kg = 600 gm
∴ 60% of it is carbon
So weight of carbon=600×$\frac{60}{100}$=360 g
∴ moles of carbon =$\frac{360}{12}$=30 moles
C(12 moles)+O2⟶CO2
C(18moles(60% of total carbon)+$\frac{1}{2}$O2⟶CO
∴Heat generated =12×400+18×100
=6600 kJ
So, the correct option is (D): 6600 kJ.