Question

Which of the following reactions can reach equilibrium in open vessel?

• A. ${NH}_{4}HS\rightleftharpoons {NH}_{3\left(g\right)}+H_2{S}_{\left(g\right)}$
• B. $N_{2\left(g\right)}+3H_{2\left(g\right)}\rightleftharpoons 2{NH}_{3\left(g\right)}$
• C. $N_{2\left(g\right)}+H_2{SO}_{4\left(aq\right)}\rightleftharpoons Ba{SO}_{4\left(g\right)}+H{Cl}_{aq}$
• D. None of these

Answer 1

Answer: (A)

${NH}_{4}HS\rightleftharpoons {NH}_{3\left(g\right)}+H_2{S}_{\left(g\right)}$

It is a common observation that most of the reactions when carried out in closed vessels do not go to completion, under a given set of conditions of temperature and pressure. In fact in all such cases, in the initial state, only the reactants are present but as the reaction proceeds, the concentration of reactants decreases and that of products increases. Finally a stage is reached when no further change in concentration of the reactants and products is observed.
So equilibrium can be achieved only if in the system two opposing processes takes place simultaneously.
so equilibrium is ahieved only in closed vessel.
conclusion: any of the given equilibrium reaction cannot achieve in open vessel.