The hydronium ion concentration in pure water is 1 × 10-7 mol L-1. The degree of dissociation of water is

Question

The hydronium ion concentration in pure water is 1 × 10-7 mol L-1. The degree of dissociation of water is (A) 1.8 × 10-9 (B) 0.8 × 10-8 (C) 9.8 × 10-6 (D) 3 × 10-9

Tardigrade Admin · Accepted Answer

If α is degree of dissociation H2O leftharpoons H++OH- Initial conc. C mol L-1 Equi. cone.: C(1-α) C α C α [H+]=C α or α=([H]+/C)=(1×10-7/55.5) =1.8 × 10-9

Q. The hydronium ion concentration in pure water is $1 \times 1 0^{- 7}$ $m o l L^{- 1}$ . The degree of dissociation of water is

$1.8 \times 1 0^{- 9}$

$0.8 \times 1 0^{- 8}$

$9.8 \times 1 0^{- 6}$

$3 \times 1 0^{- 9}$

If $α$ is degree of dissociation
$H_{2} O ⇌ H^{+} + O H^{-}$
Initial conc. $C m o l L^{- 1}$
Equi. cone. : $C (1 - α) C α C α$
$[H^{+}] = C α$ or $α = \frac{[ H ] ^{+}}{C} = \frac{1 \times 1 0 ^{- 7}}{55.5}$
$= 1.8 \times 1 0^{- 9}$

Q. The hydronium ion concentration in pure water is 1×10−7 molL−1. The degree of dissociation of water is

1.8×10−9

0.8×10−8

9.8×10−6

3×10−9