CBSE Class 12 Chemistry 2016 Outside Delhi Set 1 Solved Paper

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Question : 15
Total: 26
Calculate the boiling point of solution when 4g of MgSO4(M=120gmol1) was dissolved in 100 g of water, assuming MgSO4 undergoes complete ionization.
(Kb for water =0.52Kkgmol1)
Solution:  
Tb=iKbm
i=2
=i×Kb×
W2×1000
M×W1

=2×0.52Kkgmol1 ×
4g×1000gkg
120gmol×100g

=
2×0.52
3

=0.346K
Boiling point of water =373.15K373K
Tb=Tb0+Tb
=373.15K+0.346K or 373K+0.346K
=373.496K or 373.346K
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