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QJEEM23Cheabb: JEE Main 2023 Chemistry - Class 11 JEEM23Cheabb Solution: A mixture of 1 mole of and 1 mole of is taken in a 10 litre…

A mixture of 1 mole of H2O\mathrm{H}_{2} \mathrm{O} and 1 mole of CO\mathrm{CO} is taken in a 10 litre container and heated to 725 K725 \mathrm{~K} . At equilibrium 40%40 \% of water by mass reacts with carbon monoxide according to the equation :

CO(g)+H2O(g)⇌CO2( g)+H2( g)\mathrm{CO}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g}) \rightleftharpoons \mathrm{CO}_{2}(\mathrm{~g})+\mathrm{H}_{2}(\mathrm{~g}) .

The equilibrium constant Kc×102\mathrm{K}_{\mathrm{c}} \times 10^{2} for the reaction is ____________. (Nearest integer)

Step-by-Step Verified Solution

The given reaction is :

CO(g)+H2O(g)⇌CO2(g)+H2(g)\mathrm{CO(g)} + \mathrm{H_{2}O(g)} \rightleftharpoons \mathrm{CO_{2}(g)} + \mathrm{H_{2}(g)}

We are given that 40%40\% of water by mass reacts with carbon monoxide.

The molecular weight of water (H2O) is approximately 18 g/mol18 \, \mathrm{g/mol} , so 1 mole1 \, \mathrm{mole} of water weighs 18 g18 \, \mathrm{g} . Therefore, the mass of the reacted water is 0.40×18 g=7.2 g0.40 \times 18 \, \mathrm{g} = 7.2 \, \mathrm{g} .

Since from the stoichiometry of the reaction we can see that 1 mole1 \, \mathrm{mole} of CO reacts with 1 mole1 \, \mathrm{mole} of H2O to form 1 mole1 \, \mathrm{mole} of CO2 and 1 mole1 \, \mathrm{mole} of H2, this means that 7.2 g7.2 \, \mathrm{g} of H2O is equivalent to 7.2 g/18 g/mol=0.4 mole7.2 \, \mathrm{g} / 18 \, \mathrm{g/mol} = 0.4 \, \mathrm{mole} .

We start with 1 mole1 \, \mathrm{mole} of CO and 1 mole1 \, \mathrm{mole} of H2O. At equilibrium, we have :

- CO: 1 mole−0.4 mole=0.6 mole1 \, \mathrm{mole} - 0.4 \, \mathrm{mole} = 0.6 \, \mathrm{mole}

- H2O : 1 mole−0.4 mole=0.6 mole1 \, \mathrm{mole} - 0.4 \, \mathrm{mole} = 0.6 \, \mathrm{mole}

- CO2 : 0 mole+0.4 mole=0.4 mole0 \, \mathrm{mole} + 0.4 \, \mathrm{mole} = 0.4 \, \mathrm{mole}

- H2 : 0 mole+0.4 mole=0.4 mole0 \, \mathrm{mole} + 0.4 \, \mathrm{mole} = 0.4 \, \mathrm{mole}

The volume of the container is 10 litres10 \, \mathrm{litres} . Therefore, we can convert the moles to concentrations (in M = moles/L) as :

- [CO] = 0.6 M0.6 \, \mathrm{M}

- [H2O] = 0.6 M0.6 \, \mathrm{M}

- [CO2] = 0.4 M0.4 \, \mathrm{M}

- [H2] = 0.4 M0.4 \, \mathrm{M}

The equilibrium constant KcK_{c} for the reaction can be calculated as :

Kc=[CO2][H2][CO][H2O]K_{c} = \frac{[\mathrm{CO_{2}}][\mathrm{H_{2}}]}{[\mathrm{CO}][\mathrm{H_{2}O}]}

So, substituting the values we get :

Kc=(0.4×0.4)(0.6×0.6)=0.44K_{c} = \frac{(0.4 \times 0.4)}{(0.6 \times 0.6)} = 0.44

As per the question, we need to calculate the value of Kc×102K_{c} \times 10^{2} :

Kc×102=0.44×102=44 (rounded to the nearestinteger)K_{c} \times 10^{2} = 0.44 \times 10^{2} = 44 \, (\text{rounded to the nearestinteger})

Therefore, Kc×102=44K_{c} \times 10^{2} = 44 .

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