Question

Consider two reactions having same Arrhenius factor A, but different energy of activation.

(i) $A \rightarrow B; \, Ea_{1}=20 \, kJ$

(ii) $C \rightarrow D; \, Ea_{2}=30 \, kJ$

Both are at temperature $25^\circ C$

If temperature in both reaction is increased slightly in such a way that change in temperature in both case is same than choose the correct options.

• A. The second reaction is faster
• B. The second reaction is more sensitive towards temperature variation
• C. If temperature increases, rate of first reaction increase more sharply
• D. All the above are correct

Answer 1

Answer: (B)

Arrhenius equation;

$d\left(l n k\right)=\frac{E_{a}}{R T^{2}}dT$

Here, T and dT same and positive

$d\left(l n k\right)\alpha E_{a}$

$lnk_{2}-lnk_{1}\alpha E_{a}$

$ln\frac{K_{2}}{K_{1}}\alpha E_{a}$

So, if temperature increases, then rate of reaction having more $E_{a}$ increases more sharply.