Question

Identify the correct sequence of steps in an experiment to show the effect of temperature on the rate of the reaction.

(1) Measuring the volumes of $H_2$ gas liberated in the two test tubes.

(2) Heating the test tube B by $10°C$.

(3) Comparison of relative volumes of $H_2$ liberated in test tubes B and A.

(4) Addition of same concentration of $HCl$ to the two test tubes.

(5) Taking equal masses of fine granules of zinc in two test tubes A and B.

• A. 3, 4, 5, 1, 2
• B. 5, 4, 2, 1, 3
• C. 2, 1, 3, 5, 4
• D. 5, 4, 2, 3, 1

Answer 1

The correct option is B

5, 4, 2, 1, 3

The effect of temperature on reaction rate:

1. The rate of reaction increases as the temperature rises.
2. Intermolecular collisions between reactant molecules cause a chemical reaction.
3. The kinetic energy of the reactant molecules increases as the temperature rises, and hence the frequency of collisions rises.
4. This increased collision frequency could be the reason for the reaction rate doubling.

The explanation for the Correct option: (B)

The correct order of stages in an experiment to demonstrate the effect of temperature on reaction rate-

(5) Taking equal masses of fine granules of zinc in two test tubes $A$and $B$.

(4) Addition of same concentration of $HCl$ to the two test tubes.

(2) Heating the test tube $B$ by $10°C$.

(1) Measuring the volumes of $H_2$ gas liberated in the two test tubes.

(3) Comparison of relative volumes of $H_2$ liberated in test tubes $B$ and $A$.

The explanation for incorrect options:

(A) Since the correct sequence is 5, 4, 2, 1, 3, this option is incorrect.

(C) Since the correct sequence is 5, 4, 2, 1, 3, this option is incorrect.

(D) Since the correct sequence is 5, 4, 2, 1, 3, this option is incorrect.

Conclusion: Hence, option (B) is correct.