Determine the amount of CaCl₂ (i = 2.47) dissolved in 2.5 litre of water such that its osmotic pressure is 0.75 atm at 27° C.

Given-

Vant Hoff’s factor, i = 2.47

osmotic pressure, = 0.75 atm

Volume of solution = 2.5L.

To determine the amount of CaCl₂, we use vant Hoff’s equation for dilute

solutions, given as,

where, n is the number of moles of solute, R is solution constant which is equal

to the gas constant and T is the absolute temperature.

where, the molecular mass of CaCl₂ is 111, t = 300 K (27⁰C + 273 K) and R = 0.082,

Hence, the amount of CaCl₂ dissolved is 3.425g