question_answer 53)

Does the number of moles of reaction products increase, decrease or remain same when each of the following equilibria is subjected to a decrease in pressure by increasing the volume? (i)\[PC{{l}_{5}}(g)\rightleftharpoons PC{{l}_{3}}(g)+C{{l}_{2}}(g)\] (ii) \[CaO(s)+C{{O}_{2}}(g)\rightleftharpoons CaC{{O}_{3}}(s)\] (iii)\[3Fe(s)+4{{H}_{2}}O(g)\rightleftharpoons F{{e}_{3}}{{O}_{4}}(s)+4{{H}_{2}}(g)\]

Answer:

(i) \[\Delta {{n}_{g}}=2-1=1,\,\,i.e.,\,\,\Delta {{n}_{g}}>0\] On decreasing pressure, the equilibrium will shift towards forward direction, i.e., towards greater volume direction. (ii) Since, gaseous components are not present on both sides of reaction hence there will be no effect of pressure change. (iii) \[\Delta {{n}_{g}}=4-4=0\] There is no change in the number of gaseous moles hence there will be no effect of pressure change.