Question

A decinormal solution of NaCl exerts an osmotic pressure of 4.26 atm at 27°C. Calculate the degree of dissociation of NaCl.​

Answer 1

Osmotic pressure = 4.26 atm

T = 27 + 273 = 300 K

C = 0.1

R = 0.821 L atm K^-1 mol^-1

π = i CRT

i = π / CRT = 4.26 / 0.1 x 0.821 x 300 = 0.173

i = Observed moles / Total moles = 1 + α / 1

i = 1 + α

0.173 = 1 + α

α = 1 - 0.173 = 0.827 = 82.7 %

Answer 2

Osmotic pressure = 4.26 atm

T = 27 + 273 = 300 K

C = 0.1

R = 0.821 L atm K^-1 mol^-1

π = i CRT

i = π / CRT = 4.26 / 0.1 x 0.821 x 300 = 0.173

i = Observed moles / Total moles = 1 + α / 1

i = 1 + α

0.173 = 1 + α

α = 1 - 0.173 = 0.827 = 82.7 %