\(\mathrm{C}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{CO}_{2}(\mathrm{~g})+400 \mathrm{~kJ}\) \(\mathrm{C}(\mathrm{s})+\frac{1}{2} \mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{CO}(\mathrm{~g})+100 \mathrm{~kJ}\) 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 ' \(\mathrm{CO}_{2}\) '. The heat generated when 0.6 kg of coal is burnt is \_\_\_\_ .

JEE Main · 2022 · 29 Jul 2022 · Shift 2 · Chemical Thermodynamics

C (s) + O_{2} (g) \to CO_{2} (g) + 400 kJ

C (s) + \frac{1}{2} O_{2} (g) \to CO (g) + 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 '

CO_{2}

'.
The heat generated when 0.6 kg of coal is burnt is
____ .

(A)1600 kJ
(B)3200 kJ
(C)4400 kJ
(D)6600 kJ✓ Correct

Answer: (D)

Solution

Mass of coal = 0.6 kg = 600 g. Pure carbon = 60% of 600 g = 360 g.

Moles of carbon = 360/12 = 30 mol.

60% of carbon → CO: 0.6 × 30 = 18 mol.
40% of carbon →

CO_{2}

: 0.4 × 30 = 12 mol.

Heat from CO formation: 18 mol × 100 kJ/mol = 1800 kJ.
Heat from

CO_{2}

formation: 12 mol × 400 kJ/mol = 4800 kJ.

Total heat = 1800 + 4800 = 6600 kJ.

Answer: (D) 6600 kJ

JEE Main · 2022 · 29 Jul 2022 · Shift 2 · Single correct option

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JEE Main · 2022 · 29 Jul 2022 · Shift 2 · Chemical Thermodynamics

Solution

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