Graph of half life of first-order reaction and initial concentration of reactant is a (straight line/parabola).

For the reaction- $2\mathrm{A}+\mathrm{B} \to {\mathrm{A}}_2\mathrm{B},$

The rate $= \mathrm{k} \left[\mathrm{A}\right] [\mathrm{B}{]}^2$ with $\mathrm{k}=2.0\times {10}^{-6} {\mathrm{mol}}^{-2} {\mathrm{L}}^2 {\mathrm{s}}^{-1}$. Calculate the initial rate of reaction when $\left[\mathrm{A}\right]=0.1 \mathrm{mol} {\mathrm{L}}^{-1}$, $\left[\mathrm{B}\right]=0.2 \mathrm{mol} {\mathrm{L}}^{-1}$. Calculate the rate of reaction after $\left[\mathrm{A}\right]$ is reduced to $0.06 \mathrm{mol} {\mathrm{L}}^{-1}$.