Which of the following are true regarding a catalyst? <br> 1. It is a substance which increases the rate of reaction. <br> 2. It is a substance which reduces the activation energy. <br> 3. It is a substance which increases the activation energy. <br> 4. It is a substance which is consumed in the reaction.

Question

$\begin{array}{1 1} (a) l\; and\; 2 \\ (b) 2\; and\; 3 \\ (c) 3\; and\; 4 \\ (d) l\; and\; 4\end{array} $