Import Question JSON

$\text{Hint: Use the basic concept of equilibrium.}$ $\text{Let's analyze each statement:}$ $\text{Option 1: In an equilibrium mixture of ice and water kept in a perfectly insulated flask, the mass of ice and water does not change with time. This is correct. At equilibrium, the rate of melting equals the rate of freezing, so the masses remain constant.}$ $\text{Option 2: The intensity of the red colour increases when oxalic acid is added to a solution containing iron (III) nitrate and potassium thiocyanate.}$ $\text{In the reaction, Fe}^{3+} + \text{SCN}^- \rightleftharpoons [\text{Fe(SCN)}]^{2+} \text{ (Red)}$ $\text{When oxalic acid is added, it combines with Fe}^{3+} \text{ ions, then equilibrium shifts towards the backward direction and the intensity of red colour decreases. Therefore, option 2 is incorrect.}$ $\text{Option 3: On the addition of a catalyst, the equilibrium constant value is not affected. This statement is correct. A catalyst increases the rate of both forward and backward reactions equally without affecting the position of equilibrium or the equilibrium constant.}$ $\text{Option 4: The equilibrium constant for a reaction with a negative } \Delta\text{H value decreases as the temperature increases. This is correct according to Le Chatelier's principle. For an exothermic reaction (negative } \Delta\text{H), increasing temperature favors the endothermic direction (backward reaction), so the equilibrium constant decreases.}$ $\text{Therefore, option 2 is the incorrect statement.}$