1
JEE Main 2026 (Online) 8th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Consider the following reactions in which all the reactants and products are present in gaseous state

$$ \begin{aligned} & 2 x y \rightleftharpoons x_2+y_2 \,\,\mathrm{~K}_1=2.5 \times 10^5 \\ & x y+\frac{1}{2} z_2 \rightleftharpoons x y z \,\,\mathrm{~K}_2=5 \times 10^{-3} \end{aligned} $$

The value of $\mathrm{K}_3$ for the equilibrium $\frac{1}{2} x_2+\frac{1}{2} y_2+\frac{1}{2} z_2 \rightleftharpoons x y z$ is :

A

$2.5 \times 10^{-3}$

B

$2.5 \times 10^3$

C

$1.0 \times 10^{-5}$

D

$5 \times 10^{-3}$

2
JEE Main 2026 (Online) 6th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

One mole each of He and $\mathrm{A}(\mathrm{g})$ are taken in a 10 L closed flask and heated to 400 K to establish the following equilibrium.

$$ \mathrm{A}(\mathrm{~g}) \rightleftharpoons \mathrm{B}(\mathrm{~g}) $$

$\mathrm{K}_{\mathrm{c}}$ for this reaction at 400 K is 4.0 . The partial pressures (in atm) of He and B(g) are respectively (at equilibrium)

(Assume $\mathrm{He}, \mathrm{A}(\mathrm{g})$ and $\mathrm{B}(\mathrm{g})$ behave as ideal gases)

(Given : $\mathrm{R}=0.082 \mathrm{~L} \mathrm{~atm} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$ )

A

3.28, 2.624

B

2.624, 3.28

C

3.28, 0.656

D

0.656, 6.56

3
JEE Main 2026 (Online) 5th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The reaction $\mathrm{A}(\mathrm{g}) \rightleftharpoons \mathrm{B}(\mathrm{g})+\mathrm{C}(\mathrm{g})$ was initiated with the amount ' a ' of $\mathrm{A}(\mathrm{g})$. At equilibrium it is found that the amount of $\mathrm{A}(\mathrm{g})$ remaining is ( $\mathrm{a}-x$ ) at a total pressure of p .

The equilibrium constant Kp of the reaction can be calculated from the expression :

A

$$ \text { } \frac{x^2}{\mathrm{a}^2+x^2} \times \mathrm{p} $$

B

$$ \frac{x^2}{a^2-x^2} \times p $$

C

$$ \frac{\mathrm{a}+x^2}{x^2} \times \mathrm{p} $$

D

$$ \frac{\mathrm{a}^2-x^2}{x^2} \times \mathrm{p} $$

4
JEE Main 2026 (Online) 4th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

At $\mathrm{T}(\mathrm{K})$, the equilibrium constant of

$\mathrm{A}_2(g)+\mathrm{B}_2(g) \rightleftharpoons \mathrm{C}(g)$ is $2.7 \times 10^{-5}$.

What is the equilibrium constant for

$\frac{1}{3} \mathrm{~A}_2(\mathrm{~g})+\frac{1}{3} \mathrm{~B}_2(\mathrm{~g}) \rightleftharpoons \frac{1}{3} \mathrm{C}(\mathrm{g})$ at the same temperature?

A

$\left(2.7 \times 10^{-5}\right)^3$

B

$6 \times 10^{-2}$

C

$\sqrt{2.7 \times 10^{-5}}$

D

$ 3\times 10^{-2}$

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