Question

The pH value of decinormal solution of `NH_(4)OH` which is 20% ionised, is
A. `13.30`
B. `14.70`
C. `12.30`
D. `12.95`

Answer 1

Correct Answer - C
For `NH_(4)OH`.
`[OH^(-)] = C.alpha , c = (1)/(10)M, alpha = 0.2`
`[OH^(-)] = (1)/(10) xx 0.2 = 2 xx 10^(-2)M`
`pOH = - log [OH^(-)] = log[2 xx 10^(-2)], pOH = 1.7`
`pH = 14 - pOH = 14-1.7 = 12.30`.