$100 \ mL$ of a solution contains $0.1 \ M$ $NH_4OH$ and $0.1 \ M$ $NH_4Cl$. The $pH$ of the solution will not change on adding :-

$A$ certain buffer solution contains equal concentration of $X^{-}$ and $HX$. The $K_b$ for $X^{-}$ is $10^{-10}$. The $pH$ of the buffer is

$50 \, mL$ of $0.1 \, M \, CH_3COOH$ is being titrated against $0.1 \, M \, NaOH$. When $25 \, mL$ of $NaOH$ has been added,the $pH$ of the solution will be $.... \times 10^{-2}$. (Nearest integer)
(Given : $pK_a(CH_3COOH) = 4.76$)
$\log 2 = 0.30$,$\log 3 = 0.48$,$\log 5 = 0.69$,$\log 7 = 0.84$,$\log 11 = 1.04$

$50 \ mL$ of $2 \ N$ acetic acid mixed with $10 \ mL$ of $1 \ N$ sodium acetate solution will have an approximate $pH$ of:

If a small amount of sodium acetate is added to an equimolar mixture of sodium acetate and acetic acid,the $pH$ of the resulting solution will .......

Calculate the $pH$ of a buffer solution containing $0.04 \ M$ $NaF$ and $0.02 \ M$ $HF$ $[pK_a = 3.142]$.