Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Na_2S_2O_3 + BaCl_2 \longrightarrow BaS_2O_3 \downarrow + 2NaCl$

In the reaction $SnCl_2(excess) + HgCl_2 \rightarrow A + SnCl_4$,'$A$' is

Assign $A, B, C, D$ for the given type of reaction:
$Mn(NO_3)_2 + 2NaOH \longrightarrow Mn(OH)_2 \downarrow + 2NaNO_3$

$2 Cu_2O_{(s)} + Cu_2S_{(s)} \longrightarrow 6 Cu_{(s)} + SO_{2(g)}$
In the above reaction,the oxidant and reductant respectively are:

Given below are two statements:
Statement-$I$ : Heating $NaCl$ with concentrated $H_2SO_4$ and $MnO_2$ results in oxidation of $Mn$.
Statement-$II$ : Heating $NaI$ with concentrated $H_2SO_4$ and $MnO_2$ results in reduction of $Mn$.
In light of the above statements, choose the most appropriate answer from the options given below:

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Na_2CO_3 + 2AgNO_3 \longrightarrow Ag_2CO_3(s) + 2NaNO_3(aq)$