Question

99. 0.8 M NaCl solution is isotonic with \( 1 M H _{3} PO _{3} \) solution. Then \( \% \) dissociation of \( H _{3} PO _{3} \) will be - (1) 80 (2) 60 (3) 30 (4) 20

Answer 1

Given isotonic so 
i₁C₁RT = i₂C2RT
i₁=2 (NaCl)

i_2=?

Cancelling out RT 
we get 0.8x2/1 = 1.6

degree of dissociation = (i - 1 / n - 1) x 100

n for H₃PO₄ = 4 
(1.6 - 1 / 3)x100 = 20%