When mercuric iodide is added to the aqueous solution of potassium iodide, then:

Options

A. freezing point is raised
B. freezing point is lowered
C. freezing point does not change
D. boiling point does not change

Answer

A

Explanation

KI reacts with `HgI_(2)` to form a complex as
`2KI+HgI_(2)rarrK_(2)[HgI_(4)]overset("ionizes")rarr`
`underset("4 ions")ubrace(2K^(+)+2I^(-))" "underset("3 ions")ubrace(2K^(+)+HgI_(4)^(2-))`
Thus, number of ions decreases in the solution. Hence depression in freezing point is less, i.e., actual freezing point is raised.