The decreasing order of osmotic pressures of 10 g glucose `(P_1), " 10 g urea " (P_2)` and 10 g sucrose `(P_3)` at 273 K when dissolved in 250 mL of water separately is

Options

A. `P_1 gt P_2 gt P_3`
B. `P_2 gt P_3 gt P_1`
C. `P_2 gt P_1 gt P_3`
D. `P_3 gt P_2 gt P_1`

Answer

C

Explanation

All solutes are non-electrolytes.
`:. " Osmotic pressure, " P=(wRT)/(MxxV)`
`:. P prop w/M`
`M_("glucose") = 180, M_("urea") = 60, M_("sucrose") = 342`
`P_1 = 10/180 , P_2 10/60 , P_3 = 10/342`
`:.` The decreasing order of osmotic pressure is,
`" urea " gt " glucose " gt " sucrose or " P_2 gt P_1 gt P_3`.