Question

pH of a mixture containing $0.10M{X}^{-}$ (base) and $0.20MHX$ with $p{K}_b(X)=4$ is:

• A. $4+\log 2$
• B. $4-\log 2$
• C. $10+\log 2$
• D. $10-\log 2$

Answer 1

Answer: (D)

By Henderson's equation,
$pOH=p{K}_b+\log \frac{[HX]}{\left[X^{-}\right]}=4+\log 2$
$\therefore pH=14-pOH=10-\log 2.$