Question

The effect of addition of helium gas to the following reaction in equilibrium state, is : $PCl _5( g ) \rightleftharpoons PCl _3( g )+ Cl _2( g )$

• A. addition of helium will not affect the equilibrium.
• B. the equilibrium will shift in the forward direction and more of $Cl _2$ and $PCl _3$ gases will be produced.
• C. the equilibrium will go backward due to suppression of dissociation of $PCl _5$.
• D. helium will deactivate $PCl _5$ and reaction will stop.

Answer 1

Answer: (B)

the equilibrium will shift in the forward direction and more of $Cl _2$ and $PCl _3$ gases will be produced.

Answer 2

PCI5​(g)⇌PCl3​(g)+Cl2​(g)
(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.