Question

The rate for the following reaction is given by: \[ A + B \rightarrow C, \quad \text{Rate} = k[A][B]^2 \] How is the rate affected if we double the concentration of B?

Hint:

If rate ∝ [B]², doubling B increases rate by 4× (square dependence rule).

Answer 1

Given: \[ \text{Rate} = k[A][B]^2 \] If concentration of \( B \) is doubled: \[ [B] \rightarrow 2[B] \] New rate: \[ \text{Rate}' = k[A](2[B])^2 = k[A] \cdot 4[B]^2 \] \[ \text{Rate}' = 4 \times \text{original rate} \]
Answer: Rate becomes four times.