At $298 \text{ K}$,a certain buffer solution contains equal concentrations of $X^-$ and $HX$. The $K_b$ for $X^-$ is $10^{-10}$. What is the $pH$ of this buffer solution?

$A$ buffer solution is prepared with a concentration of $0.30 \ M \ NH_3$ and $0.20 \ M \ NH_4^+$. If the equilibrium constant for $NH_3$ is $K_b = 1.8 \times 10^{-5}$,what will be the $pH$ of this solution?

$A$ buffer solution is prepared by mixing $10 \ mL$ of $1.0 \ M$ acetic acid and $20 \ mL$ of $0.5 \ M$ sodium acetate and then diluted to $100 \ mL$ with distilled water. The $pH$ of the buffer solution is ($pK_a$ of acetic acid is $4.76$).

What is the $pH$ of a solution prepared by mixing $20 \ mL$ of $0.250 \ M$ sodium formate with $30 \ mL$ of $0.100 \ M$ $HCl$ ($pK_a$ for $HCOOH = 3.75$):-

What is the $pH$ of $10 \ L$ of a buffer solution containing $0.01 \ M \ NH_4Cl$ and $0.1 \ M \ NH_4OH$ having $pK_b$ of $5$?

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