Question

Rate of first order reaction depends upon

• A. time
• B. concentration of reactant
• C. temperature
• D. All of the above

Answer 1

Answer: (B), (C)

concentration of reactant, temperature

Answer 2

For a first order reaction, the rate law is given by

$$\text{Rate} = k[A]$$

Here, the rate depends directly on the concentration $[A]$ of the reactant. The rate constant $k$ depends on the temperature, as per the Arrhenius equation. Although the concentration $[A]$ decreases with time, the rate law itself does not have time as an independent variable.

Thus, the correct factors on which the rate depends are the concentration of the reactant and the temperature.