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For the following graphs, (a) Rate vs Time is a horizontal line, (b) t1/2 vs Initial concentration is a straight line through origin, (c) Concentration vs Time is a decreasing curve approaching zero, (d) Concentration vs Time is a horizontal line, (e) Rate vs Concentration is a straight line through origin. Choose from the options given below, the correct one regarding order of reaction is :

1. (b) zero order (c) and (e) First order
2. (a) and (b) Zero order (e) First order
3. (b) and (d) Zero order (c) and (e) First order
4. (a) and (b) Zero order (c) and (e) First order

Correct answer: (b) zero order (c) and (e) First order

Solution

Option (b) indicates that the half-life is constant regardless of initial concentration, characteristic of zero-order reactions. Options (c) and (e) show that the concentration decreases exponentially over time and that the rate is directly proportional to concentration, which are both indicative of first-order kinetics.

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