The volume of a given mass of a gas is 100ml at ${100}^{\circ }\mathrm{C}$. If pressure is kept constant at what temperature will the sample have the volume of 200ml?

Given ${\mathrm{V}}_1=100\mathrm{ml}$

${\mathrm{V}}_2=200\mathrm{ml}$ and

${\mathrm{T}}_1={100}^{\circ }\mathrm{C}=100+273=373\mathrm{K}$

We need to find the value of ${\mathrm{T}}_2$

Now 

$$\begin{gathered} {\mathrm{V}}_1{\mathrm{T}}_2={\mathrm{V}}_2{\mathrm{T}}_1 \\ \Rightarrow {\mathrm{T}}_2=\frac{{\mathrm{V}}_2{\mathrm{T}}_1}{{\mathrm{V}}_1} \\ \Rightarrow {\mathrm{T}}_2=\frac{200\times 373}{100} \\ \Rightarrow {\mathrm{T}}_2=746 \mathrm{K} \end{gathered}$$

Therefore, $$\begin{gathered} {\mathrm{T}}_2=746-273 \\ ={473}^{\circ }\mathrm{C} \end{gathered}$$

Hence, the correct option is option B.