Identify the product when phenol is heated with zinc dust.

Identify the product '$$\mathrm{B}$$' in the following reaction.

Dry ice $$\mathrm{\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{Dry\,ether}^{C{H_3}MgBr}}}$$ A $$\mathrm{\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{dil.\,HCl}^{{H_2}O}}}$$ B

Which among the following reactions exhibits $$\Delta \mathrm{H}=\Delta \mathrm{U}$$ ?

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.