Question

4 moles of ammonia are allowed to dissociate
in a vessel of 2 litres capacity. The total
number of moles of all the species of the
reaction 2NH3 + N2 + 3H2 at equilibrium, if
the degree of dissociation of ammonia is 0.5
are :​

Answer 1

Answer : The total number of moles all the species at equilibrium are 5 moles.

Solution :

The given equilibrium reaction is,

                           $2NH_3\rightleftharpoons N_2+3H_2$

Initial moles        4             0      0

At equilibrium    $(4-2\alpha)$   $\alpha$      $3\alpha$

Given :

$\alpha$ = degree of dissociation = 0.5

Total number of moles all the species at equilibrium = $(4-2\alpha)+\alpha+3\alpha$

Now put the value of degree of dissociation in this expression, we get:

Total number of moles all the species at equilibrium = $(4-2\times 0.5)+0.5+3\times 0.5$

Total number of moles all the species at equilibrium = 5 moles

Hence, the total number of moles all the species at equilibrium are 5 moles.