Metal + dil. HCl A B (white ppt.) A C Metal (M) — s Block Elements Chemistry Question

Question

Metal + dil. HCl $\rightarrow$ A $\xrightarrow{\text{Na}_2\text{HPO}_4 / \text{NH}_4\text{OH}}$ B (white ppt.) A $\xrightarrow{\text{HCl(g), Heated}}$ C $\xrightarrow{\text{Electrolysis in presence of NaCl}}$ Metal (M)