Question

Consider the equilibrium: \[ \text{CO(g)} + \text{3H}_2\text{(g)} \rightleftharpoons \text{CH}_4\text{(g)} + \text{H}_2\text{O(g)} \] If the pressure applied over the system increases by two fold at constant temperature then:

• A. (A) and (B) only
• B. (A), (B) and (D) only
• C. (B) and (C) only
• D. (A), (B) and (C) only

Hint:

Le Chatelier's principle helps predict the direction of equilibrium shifts when a system is disturbed. Increasing pressure favors the side with fewer gas molecules in a reaction.

Answer 1

The Correct Option is A

Per Le Chatelier's principle, an increase in pressure on a gaseous system favors the side with fewer moles of gas. In the provided equilibrium reaction, the reactant side exhibits 4 moles of gas (1 mole CO and 3 moles H\(_2\)), while the product side has 2 moles of gas (1 mole CH\(_4\) and 1 mole H\(_2\)O). Consequently, an elevated pressure will displace the equilibrium to the right (forward direction), resulting in an augmented concentration of products and a diminished concentration of reactants.
- (A) The concentrations of reactants and products escalate due to the equilibrium shifting toward the products. 
- (B) The equilibrium will advance in the forward direction, yielding increased quantities of CH\(_4\) and H\(_2\)O. 
- (C) The equilibrium constant remains invariant, as pressure does not influence its value at a constant temperature. 
Thus, the correct selection is (1) comprising only (A) and (B).