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

Step 1. For a first order reaction, $\text{Rate}=k[A]$; doubling $[A]$ directly doubles the Rate (since k stays fixed) -- so the ASSERTION is TRUE.

Step 2. The REASON claims the rate CONSTANT also doubles. But Section 7.3's own comparison table states explicitly that the rate constant does NOT depend on the initial concentration of reactants -- k is a fixed number at a given temperature, completely unaffected by how much A …

Evaluate the assertion and reason independently against the definitions of rate and rate constant, rather than assuming a pl …

• Assuming that because 'rate doubles' is true, whatever 'explains' it (here, the reason) must also be true -- the assertion and reason …