Liquid X has a normal boiling point of $350\mathrm{K}$, molar mass $100\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ and ${\Delta }_{\mathrm{vap}}H=30.0\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$. Use $K_b=\frac{R{T}_b^2{M}_1}{1000{\Delta }_{\mathrm{vap}}H}$ (with $M_1$ in $\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$, ${\Delta }_{\mathrm{vap}}H$ in $\mathrm{J}\mathrm{mo}{\mathrm{l}}^{-1}$) and $R=8.314\mathrm{J}\mathrm{mo}{\mathrm{l}}^{-1}{\mathrm{K}}^{-1}$. Which statements are correct?

1. A$K_b$ would be unchanged if the molar mass of the solvent were doubled, with the other data fixed
2. BIf ${\Delta }_{\mathrm{vap}}H$ were doubled with $T_b$ and $M_1$ unchanged, $K_b$ would be halved
3. CA $0.50\mathrm{mol}\mathrm{k}{\mathrm{g}}^{-1}$ solution of a non-volatile non-electrolyte in X boils at about $351.4\mathrm{K}$
4. D$K_b$ of X is about $3.4\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$