What is obtained when solutions of $KI$ and $CuSO_4$ are mixed?

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

$(NH_4)_2Cr_2O_7$ (Ammonium dichromate) is used in fireworks. The green coloured powder blown in air is

Assign $A, B, C, D$ from the given type of reaction.
$Sr(AcO)_2 + Ag_2SO_4 \longrightarrow 2AcOAg \downarrow + SrSO_4 \downarrow$

In which of the following reactions, chlorine acts as an oxidising agent?
$(i)$ $CH_3CH_2OH + Cl_2 \longrightarrow CH_3CHO + HCl$
(ii) $CH_3CHO + Cl_2 \longrightarrow CCl_3CHO + HCl$
(iii) $CH_4 + Cl_2 \stackrel{hv}{\longrightarrow} CH_3Cl + HCl$
The correct answer is

Purple solution of $KMnO_4 \xrightarrow{Na_2SO_4, BaCl_2}$ Pink ppt. Select the correct statement about pink ppt.