Q58 / 180 · KCET 2020 · Chemistry

The rate constant of a reaction is given by $k=P Z e^{-E_{a} / R T}$ under standard notation. In order to speed up the reaction, which of the following factors has to be decreased?

  • A
    $Z$
  • B
    Both $Z$ and $T$
  • Correct answer
    C
    $E_{a}$
  • D
    $T$

Solution

$\therefore k=P Z e^{-E a / R T}$ The above reaction expression is given in terms of exponents. We have to increase the speed of reaction. So, value of $k$ has to be more and as per the given expression. $k \propto \frac{1}{e^{E_{a} / R T}}$ if $E a$ decreases, than $\left[e^{E_{a} / R T}\right]$ also decreases and $\left[e^{\frac{1}{E_{a} / R T}}\right]$ increases. $\therefore k$ also increases

Hence, the correct answer is option: 'C'.

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