Question

Which one of the following conditions will favour maximum formation of the product in the reaction,
$A_2\left(g\right)+B_2\left(g\right)\rightleftharpoons X_2\left(g\right){\Delta }_{r}H=-XkJ$

• A. High temperature and high pressure
• B. High temperature and low pressure
• C. Low temperature and high pressure
• D. Low temperature and hlow pressure

Answer 1

The correct option is C Low temperature and high pressure

Calculating $\Delta n_g$
$\Delta n_g=1-2=-1$
$\Delta n_g<0$
So, on increasing pressure reaction will go towards the side which has less number of gaseous moles. So, high pressure is required for high formation of products.

For temperature,
When the reaction is exothermic, on decreasing temperature, the reaction shifts towards that side where the temperature increases.
Given heat of reaction is negative so, reaction is exothermic. Here temperature increases in product side. So, low temperature is required.