Question

If the temperature is increased, how will the equilibrium of the following reaction be affected ?
$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right);△H=-30kJ/mol$

• A. It will be shifted, to the right
• B. It will be shifted to the left
• C. It will be unaffected
• D. The effect on the equilibrium cannot be determined without more information
• E. None of the above

Answer 1

The correct option is B It will be shifted to the left

If the temperature is increased, the equilibrium of the given reaction will be shifted to the left.
$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)△H=-30kJ/mol$
The negative value of the enthalpy change for the reaction indicates that heat is given out during the forward reaction.
The forward reaction is an exothermic reaction. When temperature is increased, the equilibrium will shift to left so that more and more heat is absorbed in the reverse reaction. This will nullify the effect of increased temperature.