For a dilute solution containing a nonvolatile solute,the molar mass of solute evaluated from the elevation of boiling point is given by the expression

Question

$\begin{array}{1 1}M_2=\large\frac{\Delta T_b}{K_b}\frac{m_1}{m_2}\\M_2=\large\frac{\Delta T_b}{K_b}\frac{m_2}{m_1}\\M_2=\large\frac{K_b}{\Delta T_b}\frac{m_2}{m_1}\\M_2=\large\frac{K_b}{\Delta T_b}\frac{m_1}{m_2}\end{array}$