1. Explain activation energy of the endothermic chemical reaction with diagram in presence and absence of catalyst. Also calculate rate constant of first order reaction, if half-life of reaction is 50 minutes (2 +2 Marks)

2. Define Bronsted and Lawry theory of acid and base with an example. Explain conjugated acid and base pair.

3. Explain the role of salt concentration in our body cell for thirsty feeling (requirement to drink water).