Chemistry

Problem

The gas-phase reaction

A + 2\,B \to \text{products}

follows the rate law

\text{rate} = k[A][B]^2

. Currently,

[A]_0 = 0.20\,\text{M}

and

[B]_0 = 0.10\,\text{M}

. The laboratory has only enough reagent to allow

[B]

to reach at most

0.30\,\text{M}

. Which set of new concentrations will quadruple the initial rate without exceeding the limit on

[B]

? a)

[A]=0.40\,\text{M},\;[B]=0.20\,\text{M}

[A]=0.40\,\text{M},\;[B]=0.10\,\text{M}

[A]=0.20\,\text{M},\;[B]=0.20\,\text{M}

[A]=0.20\,\text{M},\;[B]=0.30\,\text{M}