Question

The boiling point of water is $ {{100}^{o}}C $ . What will be the boiling point of an aqueous solution containing $ 0.6\,\,g $ of urea (molar mass $ =60 $ ) in $ 100\,\,g $ of water?( $ {{K}_{b}} $ for water $ =0.52\,\,K/m $ )

• A. $ {{100.052}^{o}}C $
• B. $ {{101.052}^{o}}C $
• C. $ {{120.52}^{o}}C $
• D. None of these

Answer 1

Answer: (A)

We know that, $ \Delta {{T}_{b}}=\frac{{{K}_{b}}\times {{w}_{B}}\times 1000}{{{M}_{B}}\times {{w}_{A}}} $ $ {{K}_{b}}=0.52K\,\,{{m}^{-1}},\,\,{{w}_{B}}=0.6\,\,g,\,\,{{M}_{b}}=60 $ $ {{w}_{A}}=100\,\,g $ $ \therefore $ $ \Delta {{T}_{b}}=\frac{0.52\times 0.6\times 1000}{60\times 1000}={{0.052}^{o}}C $ Thus boiling point of the solution $ =100+0.052={{100.052}^{o}}C $