JEE Main 2023 — Chemistry Physical Chemistry

2023mcqmedium

The effect of addition of helium gas to the following reaction in equilibrium state at constant volume, is :

${\mathrm{PCI}}_{5}(g)\rightleftharpoons {\mathrm{PCl}}_{3}(g)+{\mathrm{Cl}}_{2}(g)$

Official previous-year question

Held on 1 Feb 2023 · Verified 6 Jul 2026.

Options

A
the equilibrium will shift in the forward direction and more of ${\mathrm{Cl}}_{2}$ and ${\mathrm{PCl}}_{3}$ gases will be produced.
B
the equilibrium will go backward due to suppression of dissociation of ${\mathrm{PCl}}_{5}$ .
C
helium will deactivate ${\mathrm{PCl}}_{5}$ and reaction will stop.
D
addition of helium will not affect the equilibrium.

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Solution

${\mathrm{PCI}}_{5}(g)\rightleftharpoons {\mathrm{PCl}}_{3}(g)+{\mathrm{Cl}}_{2}(g)$

In the above reaction vessel, when helium(an inert gas) is added following cases can happen for isobaric and isochoric processes respectively:

Case 1 : At constant P - volume will increase so reaction will shift in forward direction then answer will be A

Case 2 : At constant volume no change in active mass so reaction will not shift in any direction then answer will be D.

Thus, at constant volume, addition of helium will not have any impact on the equilibrium.

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Options

the equilibrium will shift in the forward direction and more of ${\mathrm{Cl}}_{2}$ and ${\mathrm{PCl}}_{3}$ gases will be produced.

the equilibrium will go backward due to suppression of dissociation of ${\mathrm{PCl}}_{5}$ .

helium will deactivate ${\mathrm{PCl}}_{5}$ and reaction will stop.

addition of helium will not affect the equilibrium.

Solution

${\mathrm{PCI}}_{5}(g)\rightleftharpoons {\mathrm{PCl}}_{3}(g)+{\mathrm{Cl}}_{2}(g)$

In the above reaction vessel, when helium(an inert gas) is added following cases can happen for isobaric and isochoric processes respectively:

Case 1 : At constant P - volume will increase so reaction will shift in forward direction then answer will be A

Case 2 : At constant volume no change in active mass so reaction will not shift in any direction then answer will be D.

Thus, at constant volume, addition of helium will not have any impact on the equilibrium.

JEE Main 2023 — Chemistry Physical Chemistry

Options

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Solution

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JEE Main 2023 — Chemistry Physical Chemistry

Options

Did you get this right?

Solution

Your note

JEE Main Physical Chemistry in other years

More JEE Main Physical Chemistry questions

Other Chemistry topics for JEE Main

Organic Chemistry

Inorganic Chemistry

Keep practicing Physical Chemistry