Which one of the following pairs of solutions can we expect to be isotonic at the same temperature?

Options

A. 0.1 M urea and 0.1 M NaCl
B. 0.1 M urea and 0.2 M `MgCl_2`
C. 0.1 M NaCl and 0.1 M `Na_2SO_4`
D. 0.1 M Ca(NO3)2 and 0.1 M `Na_2SO_4`

Answer

D

Explanation

Only for the pair of `Ca(NO_3)_2 and Na_2SO_4` value of .i. is same.
`Ca(NO_3)_2 to Ca^(2+) + 2NO_3^-, i = 3`
`Na_2 SO_4 to 2Na^(+)+ SO_3^-,i = 3`