1.
What is the freezing point of a solution containing 8.1 gm8.1\,\text{gm} of HBr in 100 gm100\,\text{gm} water assuming the acid to be 90%90\% ionised (KfK_f for water =1.86 K⋅molality−1= 1.86\,\text{K·molality}^{-1})?