A buffer solution is prepared by mixing 0.2 M sodium acetate and 0.1 M acetic acid. If pK$$_a$$ for acetic acid is 4.7, find the pH.

Which salt from following forms aqueous solution having $$\mathrm{pH}$$ less than 7 ?

Solubility of a salt $$\mathrm{A}_2 \mathrm{~B}_3$$ is $$1 \times 10^{-3} \mathrm{~mol} \mathrm{~dm}^{-3}$$. What is the value of its solubility product?

The $$\left[\mathrm{OH}^{-}\right]$$ in a solution is $$1 \times 10^{-12} \mathrm{~mol} \mathrm{~dm}{ }^{-3}$$. What is the concentration of $$\mathrm{H}^{+}$$ ions?