Question

For the reaction : $P\rightleftharpoons Q+R$. Initially $2$ mol of $P$ was taken. Up to equilibrium $0.5$ mol of $P$ was dissociated. What would be the degree of dissociation:

• A. $0.5$
• B. $1$
• C. $0.25$
• D. $4.2$

Answer 1

The correct option is C $0.25$

$2$ mole of $P$

At equilibrium, $0.5$ mole dissociation.

Degree of dissociation - number of ions dissociated from the solute. It denoted by $\alpha$.

$\alpha =\frac{moledissociated}{molepresentinitial}$

$\alpha =\frac{0.5}{2.0}=0.25$

Hence, option(c) is the correct answer.