$AgCl$ on fusion with $Na_2CO_3$ forms

To an acidified dichromate solution,a pinch of $Na_2O_2$ is added and shaken. What is observed?

Match the chemical reactions given in List-$I$ with their types given in List-$II$:

List-$I$	List-$II$
$A$. $TiCl_{4(l)} + 2Mg_{(s)} \xrightarrow{\Delta} Ti_{(s)} + 2MgCl_{2(s)}$	$I$. Disproportionation reaction
$B$. $2H_2O_{2(aq)} \rightarrow 2H_2O_{(l)} + O_{2(g)}$	$II$. Metal displacement reaction
$C$. $C_{(s)} + O_{2(g)} \xrightarrow{\Delta} CO_{2(g)}$	$III$. Decomposition reaction
$D$. $2NaH_{(s)} \xrightarrow{\Delta} 2Na_{(s)} + H_{2(g)}$	$IV$. Combination reaction

Consider the following redox reaction in basic medium.
$x \ Cr(OH)_3 + y(IO_3)^{-} + z(OH)^{-} \rightarrow a(CrO_4)^{2-} + b(I)^{-} + c(H_2O)$
The incorrect option about it is

Light green crystals of ferrous sulphate lose water molecules and turn brown on exposure to air. This is due to its oxidation to:

Assign $A, B, C, D$ from the given type of reaction.
$2F_2 + 2H_2O \longrightarrow 4HF + O_2$