Ionic Equilibrium in Solution — Prelims Questions

Which of the following solutions will have the highest pH?

The $K_{sp}$ of $CaF_2$ is $3.9 \times 10^{-11}$ at $25^circ C$. What is its molar solubility in pure water?

A buffer solution is prepared by mixing $0.2,\text{M}$ $CH_3COOH$ and $0.2,\text{M}$ $CH_3COONa$. If the $pK_a$ of $CH_3COOH$ is $4.74$, what is the pH of the buffer solution?

Which of the following statements about salt hydrolysis is INCORRECT?

What is the pH of a $1.0 \times 10^{-8},\text{M}$ $HCl$ solution? (Given: $K_w = 1.0 \times 10^{-14}$ at $25^circ C$)

The $pK_a$ of acetic acid ($CH_3COOH$) is $4.74$. What is the $pK_b$ of its conjugate base, acetate ion ($CH_3COO^-$), at $25^circ C$?

Which of the following conditions would lead to the precipitation of $Mg(OH)_2$ from a solution containing $Mg^{2+}$ ions? (Given: $K_{sp}$ of $Mg(OH)_2 = 1.8 \times 10^{-11}$)