JEE Advanced 2016 Paper 2

Thermal decomposition of gaseous X‌2 to gaseous X at 298 K takes place according to the following equation :
X‌2(g)⇌2X(g)The standard reaction Gibbs energy ∆‌r G°, of this reaction is positive. At the start of the reaction, there is one mole of X‌2 and no X. As the reaction proceeds, the number of moles of X formed is given by β. Thus, β‌equilibrium is the number of moles of X formed at equilibrium. The reaction is carried out at a constant total pressure of 2 bar. Consider the gases to behave ideally.
(Given : R = 0.083 L bar K–1 mol–1)