QJEEM24Ch8a5a: JEE Main 2024 Chemistry - Class 12 JEEM24Ch8a5a Solution: For a reaction If the rate of formation of B is set to be zero…

To determine the concentration of $\mathrm{B}$ when the rate of formation of $\mathrm{B}$ is set to zero, let's consider the reaction sequence:

$\mathrm{A} \xrightarrow{\mathrm{K}_1} \mathrm{B} \xrightarrow{\mathrm{K}_2} \mathrm{C}$

The rate of formation of $\mathrm{B}$ from $\mathrm{A}$ is given by:

$\text{Rate of formation of } \mathrm{B} = \mathrm{K}_1[\mathrm{A}]$

The rate of consumption of $\mathrm{B}$ to form $\mathrm{C}$ is given by:

$\text{Rate of consumption of } \mathrm{B} = \mathrm{K}_2[\mathrm{B}]$

At steady state, where the rate of formation of $\mathrm{B}$ is set to zero, the rate of formation of $\mathrm{B}$ is equal to the rate of its consumption. Therefore, we have:

$\mathrm{K}_1[\mathrm{A}] = \mathrm{K}_2[\mathrm{B}]$

Solving for $[\mathrm{B}]$ , we get:

$[\mathrm{B}] = \frac{\mathrm{K}_1}{\mathrm{K}_2} [\mathrm{A}]$

Therefore, the correct concentration of $\mathrm{B}$ is:

Option D: $\left(\frac{\mathrm{K}_1}{\mathrm{K}_2}\right)[\mathrm{A}]$