(Solved): 4. (a) The isomerism of cis-2-butene to trans-2-butene is first order in both directions. At 25 ...

4. (a) The isomerism of cis-2-butene to trans-2-butene is first order in both directions. At 25 ${}^{?}\mathrm{C}$, the equilibrium constant is 0.406 and the forward rate constant is $4.21\times 10^{?4}{\mathrm{s}}^{?1}$. Starting with a sample of the pure cis isomer with $[\mathrm{cis}{]}_0=0.115\mathrm{mol}?{\mathrm{dm}}^{?3}$, how long would it take for half the equilibrium amount of the trans isomer to form? (b) The following reaction is found to be endothermic in nature What will happen to the concentration of $B$ at equilibrium when the temperature is suddenly raised? (Marks $=4+1=5$ ).