Question

The equation $\alpha =\frac{D-d}{(n-1)d}$ is correctly matched for:

($\alpha$ is the degree of dissociation, $D$ and $d$ are the vapour densities before and after dissociation, respectively ).

• A. $A\rightleftharpoons \frac{nB}{2}+\frac{nC}{3}$
• B. $A\rightleftharpoons \frac{nB}{3}+\left(\frac{2n}{3}\right)C$
• C. $A\rightleftharpoons \left(\frac{n}{2}\right)B+\left(\frac{n}{4}\right)C$
• D. $A\rightleftharpoons \left(\frac{n}{2}\right)B+C$

Answer 1

Answer: (B)

$A\rightleftharpoons \frac{nB}{3}+\left(\frac{2n}{3}\right)C$

$\alpha =\frac{D-d}{(n-1)d}$
$n=$ no. of moles of gaseous product in equation $\left(B\right)$.
No. of moles of gaseous
Product = $\frac{n}{3}+\frac{2n}{3}=n$
Hence choice equation fit for option ($B$).