$C +$ Conc. $H_2SO_4 \xrightarrow{\Delta} X + Y + H_2O$. $X$ and $Y$ in the above reaction are:

Assign $A, B, C, D$ from the given type of reaction.
$Na_2CO_3 + PbSO_4 \longrightarrow PbCO_3 \downarrow + Na_2SO_4$

The reaction of white phosphorus on boiling with alkali in an inert atmosphere results in the formation of product '$A$'. The reaction of $1 \ mol$ of '$A$' with an excess of $AgNO_3$ in an aqueous medium gives ............... $mol(s)$ of $Ag$. (Round off to the Nearest Integer).

The number of electrons required to reduce chromium completely in $Cr_2O_7^{2-}$ to $Cr^{3+}$ in acidic medium is:

Assign $A, B, C, D$ from the given type of reaction: $C_{(s)} + O_{2(g)} \xrightarrow{\Delta} CO_2 \uparrow$

Justify that the reaction: $2 Na ( s ) + H_2 ( g ) \rightarrow 2 NaH ( s )$ is a redox change.