Question

Define: (i) Half life of a reaction (ii) Pseudo first order reaction

Hint:

Pseudo first order reactions simplify kinetic analysis when one reactant is in large excess and its concentration effectively remains constant.

Answer 1

Step 1: Half life (\(t_{1/2}\)) is an important kinetic parameter used to study the rate of a reaction. For a first order reaction: \[ t_{1/2} = \frac{0.693}{k} \] where \(k\) is the rate constant.
Step 2: In a pseudo first order reaction, the concentration of one reactant remains nearly constant throughout the reaction. As a result, the rate depends only on the concentration of one reactant, making the reaction appear first order.
Step 3: A common example is the hydrolysis of ethyl acetate in excess water.