What is the $$\mathrm{pH}$$ of solution containing $$4.62 \times 10^{-4} \mathrm{M} \mathrm{H}^{+}$$ ions?

Which among the following salt solution in water is acidic in nature?

What is the molar concentration of acetic acid if value of it's, dissociation constant is $$1.8 \times 10^{-5}$$ and degree of dissociation is 0.02 ?

A buffer solution is prepared by mixing equimolar acetic acid and sodium acetate. If '$$\mathrm{K}_d$$' of acetic acid is $$1.78 \times 10^{-5}$$, find the $$\mathrm{pH}$$ of buffer solution.