If $$1\,g$$  of solute $$\left( {{\text{molar}}\,\,{\text{mass}} = 50\,g\,mo{l^{ - 1}}} \right)$$      is dissolved in $$50\,g$$  of solvent and the elevation in boiling point is $$1\,K.$$  The molar boiling constant of the solvent is

Solution :
$$\eqalign{ & \Delta {T_b} = {K_b} \times m \cr & {\text{or}}\,\,\,{K_b} = \frac{{\Delta {T_b}}}{m} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{1}{{\frac{1}{{50}} \times \frac{{1000}}{{50}}}} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{5}{2} \cr & \,\,\,\,\,\,\,\,\,\,\,\,\, = 2.5 \cr} $$