Question

Densities of diamond and graphite are 3.5 and 2.3 g/ml respectively. Increase of pressure on the equilibrium:

• A. Has no effect
• B. Favours forward reaction
• C. Favors backward reaction
• D. Increases the reaction rate

Answer 1

The correct option is C

Favors backward reaction

An explanation for the correct option:

Option C

• We need to use Le Chatelier’s principle of the effect of change of pressure on equilibrium reaction.
• We know that pressure and volume are inversely proportional, based on this Le Chatlier’s principle states that an increase in pressure or volume makes the equilibrium to move in the direction that decreases other quantities.
• Density of diamond $=3.5\mathrm{g}{\mathrm{mL}}^{-1}$
• The density of graphite $=2.3{\mathrm{gmL}}^{-1}$.
• As the pressure increases on the system at equilibrium, then by Le chatelier's principle the reaction will shift towards the formation of a denser product.
• Hence, the backward reaction is favored.

Therefore, option C is correct.