An example of a neutral buffer is:

The $pH$ of the blood buffer $CO_2-HCO_3^-$ is $7.4$. The ratio of conjugate base to acid is ....... $(K_a (H_2CO_3) = 4.5 \times 10^{-7})$

Calculate the amount of $(NH_4)_2SO_4$ in grams which must be added to $500 \ mL$ of $0.200 \ M \ NH_3$ to yield a solution with $pH = 9.35$ ($K_b$ for $NH_3 = 1.78 \times 10^{-5}$).

An acidic buffer is obtained on mixing

Calculate $pH$ of the solution obtained by mixing $50 \ mL$ of $0.2 \ M$ $NH_4Cl$ solution and $75 \ mL$ of $0.1 \ M$ $NaOH$ solution. Given $pK_b$ for aqueous $NH_3$ is $4.74$.

$2 \ g$ acetic acid and $3 \ g$ sodium acetate are present in $100 \ mL$ aqueous solution. What will be the $pH$ of the solution if the ionisation constant of acetic acid is $1.8 \times 10^{-5}$?