What will be the freezing point of a 0.5 m KCl solution ? The molal freezing point constant of water is `1.86^@C m^(-1)` .

Explanation

(i) There are two moles of ions per mol of NaCl. Therefore, `Delta T_(f)` cannot be equal to 1.86 and freezing point cannot be equal to `0 - 1.86 = -1.86^(@)C` .
(ii) `Delta T_(f)` cannot be equal ot `2 xx 1.86 = 3.72` and freezing point `= -3.72` because there are strong interionic attractions for lm solution so that the degree of ionization is not 100% at the freezing point. The value of i is some what less than 2.