Q. For the gaseous reaction, $C_{2}H_{4} + H_{2} \rightleftharpoons C_{2}H_{6},\ \mathrm{\Delta}H = - 130\ kJ\ mol^{- 1}$ carried in a closed vessel, the equilibrium concentration of the $C_{2}H_{6}$ can definitely be increased by
A) Increasing temperature and decreasing pressure
B) Decreasing temperature and increasing pressure
C) Increasing temperature and pressure both
D) Decreasing temperature and pressure only
Explanation
(b)
According to Le-Chatelier’s principle exothermic reactions are favourable at low pressure. The reaction in which number of moles decreases are favourable at high pressure or low volume.
$C_{2}H_{4} + H_{2} \rightleftharpoons C_{2}H_{6},\ \mathrm{\Delta}H = - 130\ kJ\ mol^{- 1}$
$\because$ The reaction is exothermic and number of moles of reactants are decreasing.
$\because$ The reaction rate is increased by decreasing temperature and increasing pressure.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.