JEE Main 2024 — Chemical Equilibrium Question with Solution

The equilibrium constant of a chemical reaction (usually denoted by the symbol K) provides insight into the relationship between the products and reactants when a chemical reaction reaches equilibrium. For example, the equilibrium constant of concentration (denoted by K_c) of a chemical reaction at equilibrium can be defined as the ratio of the concentration of products to the concentration of the reactants, each raised to their respective stoichiometric coefficients. It is important to note that there are different types of equilibrium constants that provide relationships between the products and the reactants of equilibrium reactions in terms of different units.

Equilibrium Constant Formula

$K_{\mathrm{eqb}}=\frac{{\mathrm{K}}_{\mathrm{f}}}{{\mathrm{K}}_{\mathrm{b}}}=\frac{{\left[\mathrm{C}\right]}^{\mathrm{c}}{\left[\mathrm{D}\right]}^{\mathrm{d}}}{{\left[\mathrm{A}\right]}^{\mathrm{a}}{\left[\mathrm{B}\right]}^{\mathrm{b}}}={\mathrm{K}}_{\mathrm{c}}$

Where ${\mathrm{K}}_{\mathrm{c}}$ indicates the equilibrium constant measured in moles per litre.

$K_C=\frac{\left[\mathrm{Products}\right] }{\left[\mathrm{Reactants}\right] }$

${\mathrm{K}}_{\mathrm{C}}=\frac{\left[{\mathrm{FeSCN}}^{2+}\right]}{\left[{\mathrm{Fe}}^{3+}\right]\left[{\mathrm{SCN}}^{-}\right]}$

Hence, the answer is option A.