1
JEE Main 2023 (Online) 15th April Morning Shift
Numerical
+4
-1
For a reversible reaction $\mathrm{A} \rightleftharpoons \mathrm{B}$, the $\Delta \mathrm{H}_{\text{forward reaction}} = 20 \mathrm{~kJ} \mathrm{~mol}^{-1}$. The activation energy of the uncatalysed forward reaction is $300 \mathrm{~kJ} \mathrm{~mol}^{-1}$. When the reaction is catalysed keeping the reactant concentration same, the rate of the catalysed forward reaction at $27^{\circ} \mathrm{C}$ is found to be same as that of the uncatalysed reaction at $327^{\circ} \mathrm{C}$.

The activation energy of the catalysed backward reaction is ___________ $\mathrm{kJ}~ \mathrm{mol}^{-1}$.
2
JEE Main 2023 (Online) 13th April Evening Shift
Numerical
+4
-1

A(g) $$\to$$ 2B(g) + C(g) is a first order reaction. The initial pressure of the system was found to be 800 mm Hg which increased to 1600 mm Hg after 10 min. The total pressure of the system after 30 min will be _________ mm Hg. (Nearest integer)

3
JEE Main 2023 (Online) 13th April Morning Shift
Numerical
+4
-1

$$\mathrm{t}_{87.5}$$ is the time required for the reaction to undergo $$87.5 \%$$ completion and $$\mathrm{t}_{50}$$ is the time required for the reaction to undergo $$50 \%$$ completion. The relation between $$\mathrm{t}_{87.5}$$ and $$\mathrm{t}_{50}$$ for a first order reaction is $$\mathrm{t}_{87.5}=x \times \mathrm{t}_{50}$$ The value of $$x$$ is ___________. (Nearest integer)

4
JEE Main 2023 (Online) 12th April Morning Shift
Numerical
+4
-1

The reaction $$2 \mathrm{NO}+\mathrm{Br}_{2} \rightarrow 2 \mathrm{NOBr}$$

takes places through the mechanism given below:

$$\mathrm{NO}+\mathrm{Br}_{2} \Leftrightarrow \mathrm{NOBr}_{2}$$ (fast)

$$\mathrm{NOBr}_{2}+\mathrm{NO} \rightarrow 2 \mathrm{NOBr}$$ (slow)

The overall order of the reaction is ___________.