How does a catalyst effect rate of a reaction? Give an example of specific acid catalysedreaction.

A catalyst affects the rate of a reaction by providing an alternative reaction pathway with a lower activation energy. This means that more of the reactant particles will have enough energy to undergo the reaction, which increases the rate of the reaction.

Here's a step-by-step explanation:

1. A catalyst is introduced to a reaction. This catalyst is not consumed in the reaction, meaning it can be used repeatedly.

2. The catalyst provides an alternative reaction pathway that has a lower activation energy than the original pathway.

3. Because the activation energy is lower, more reactant particles have enough energy to overcome this barrier.

4. As a result, the rate of the reaction increases because more reactant particles are able to react in a given period of time.

An example of a specific acid-catalysed reaction is the esterification reaction between an acid and an alcohol to form an ester. In this reaction, a proton from the acid catalyst (often sulfuric acid) is donated to the oxygen atom of the alcohol. This makes the oxygen atom a better leaving group, which allows the reaction to proceed more quickly. The reaction is as follows:

RCOOH + R'OH ⇌ RCOOR' + H2O

In this reaction, R and R' are any organic groups, RCOOH is a carboxylic acid, R'OH is an alcohol, and RCOOR' is an ester. The double arrow indicates that the reaction can proceed in both the forward and reverse directions.