Which statement is correct for a mixture of $1 \ M \ NaCl$ and $1 \ M \ HCl$?

$1 \times 10^{-3} \ \text{mole}$ of $HCl$ is added to a buffer solution made up of $0.01 \ \text{M}$ acetic acid and $0.01 \ \text{M}$ sodium acetate. The final $pH$ of the buffer will be (given, $pK_{a}$ of acetic acid is $4.75$ at $25^{\circ} \text{C}$)

$0.1 \, M$ acetic acid solution is titrated against $0.1 \, M \, NaOH$ solution. What would be the difference in $pH$ between $1/4$ and $3/4$ stages of neutralization of acid?

The $pH$ of blood does not appreciably change by a small addition of acid or a base because blood

In some solutions,the concentration of $H_3O^{+}$ remains constant even when small amounts of strong acid or strong base are added to them. These solutions are known as

$20 \ mL$ of $0.1 \ M$ acetic acid is mixed with $50 \ mL$ of potassium acetate. $K_a$ of acetic acid $= 1.8 \times 10^{-5}$ at $27^{\circ} C$. Calculate the concentration of potassium acetate if the $pH$ of the mixture is $4.8$. (in $M$)