Increasing amoutn of `HgI_(2)`is added to `1` litre of an aqueous solution containing`0.1`mole of `KI`.Which of the following graphs does represent the variation of depression in freezing point of the resulting solution with the amount of `HgI_(2)`added?

Options

A.
B.
C.
D.

Answer

C

Explanation

`2KI_(aq)+HgI_(2(s))rarrK_(2)HgI_(4)(aq)or2K^(+)+2I^(-)+HgI_(2(s))rarr2K^(+)+[HgI_(4)]^(2-)` As a result of complex ion formation, theno. Of mole particles in the solution decreases in the ratio `4:3`So`DeltaT_(f)`decreases until all the `I^(-)` ions are consumed with`0.05` moles of `HgI_(2)`. The excess of `HgI_(2)`remain insoluble .Hence after `0.05`moles of `HgI_(2)`, the `F.P.` of solution remains constant.