Question

Assertion : Rate of reaction doubles when concentration of reactant is doubled if it is a first order reaction.
Reason : Rate constant also doubles.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (C)

For first order reaction, Rate $_{1}=k\left[A_{1}\right]$
According to question, $\left[ A _{2}\right]=\left[2 A _{1}\right]$
$\therefore $ Rate $_{2}= k \left[2 A _{1}\right]$
$\Rightarrow$ Rate $_{2}=2$ Rate $_{1}$
For a given reaction, rate constant is constant and independent of the concentration of reactant.