Q.A solution of citric acid C6H8O7 in 50 g of acetic acid has a boiling point elevation of 1.76 K. If Kb for acetic acid is 3.07 K kg mol-1, what is the molality of solution?

Boiling point elevation is the rise in a solution's boiling point above the pure solvent's boiling point, caused by dissolving a nonvolatile solute: $\Delta T_b=T_b-T_b^0$. It follows directly from vapour pressure lowering -- since the solution's vapour pressure is lower than the pure solvent's at every temperature, the solution's vapour-pressure-vs-temperature curve sits below the solvent's …