What is formula of mustard gas?

Rate law for the reaction $\mathrm{aA}+\mathrm{bB} \rightarrow \mathrm{cC}+\mathrm{dD}$ is $r=k[A][B]$, the rate of reaction doubles if

Which of the following reactions exhibit minimum standard reduction potential?

Which from following dopants is used in germanium to produce p-type semiconductor?