Question

Consider the chemical equation in equilibrium.

Answer 1

Answer: A. The equilibrium will shift to the left to favor the reverse reaction.

Explanation:

Any change in the equilibrium is studied on the basis of Le-Chatelier's principle.

This principle states that if there is any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.

For the given equation:

$CH_4(g)+H_2O(g)\leftrightharpoons CO(g)+3H_2$

If the pressure is increased, the volume will decrease according to Boyle's Law. Now, according to the Le-Chatelier's principle, the equilibrium will shift in the direction where decrease in pressure is taking place. As the number of moles of gas molecules is lesser at the reactant side. So, the equilibrium will shift in the left direction to favor the formation of reactants in reverse reaction.

Answer 2

By increasing the P reaction moves toward less number of moles in this case 
The equilibrium will shift to the left to favor the reverse reaction.