$A$ white crystalline salt $[A]$ reacts with dilute $HCl$ to produce a suffocating gas $[B]$ and also forms a yellow precipitate. When gas $[B]$ is passed through acidified potassium dichromate,it turns the solution green,forming $[C]$. Identify $A, B$,and $C$ respectively.

Assign $A, B, C, D$ from given type of reaction.
$2KI + CuSO_4 \longrightarrow CuI \downarrow + \frac{1}{2}I_2 + K_2SO_4$

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

Identify the substance oxidised,reduced,oxidising agent,and reducing agent for each of the following reactions:
$(a)$ $2 AgBr_{(s)} + C_6 H_6 O_{2(aq)} \rightarrow 2 Ag_{(s)} + 2 HBr_{(aq)} + C_6 H_4 O_{2(aq)}$
$(b)$ $HCHO_{(l)} + 2 [Ag(NH_3)_2]^+_{(aq)} + 3 OH^-_{(aq)}$ $\rightarrow 2 Ag_{(s)} + HCOO^-_{(aq)} + 4 NH_{3(aq)} + 2 H_2 O_{(l)}$
$(c)$ $HCHO_{(l)} + 2 Cu^{2+}_{(aq)} + 5 OH^-_{(aq)} \rightarrow Cu_2 O_{(s)} + HCOO^-_{(aq)} + 3 H_2 O_{(l)}$
$(d)$ $N_2 H_{4(l)} + 2 H_2 O_{2(l)} \rightarrow N_{2(g)} + 4 H_2 O_{(l)}$
$(e)$ $Pb_{(s)} + PbO_{2(s)} + 2 H_2 SO_{4(aq)} \rightarrow 2 PbSO_{4(s)} + 2 H_2 O_{(l)}$

When $KMnO_4$ solution is titrated with a solution containing $Fe^{2+}$ ions,the indicator used in this titration is

Match List-$I$ with List-$II$.

List-$I$ (Types of redox reactions)	List-$II$ (Examples)
$a.$ Combination reaction	$(i)$ $Cl_{2(g)} + 2Br^-_{(aq)} \rightarrow 2Cl^-_{(aq)} + Br_{2(l)}$
$b.$ Decomposition reaction	$(ii)$ $2H_2O_{2(aq)} \rightarrow 2H_2O_{(l)} + O_{2(g)}$
$c.$ Displacement reaction	$(iii)$ $CH_{4(g)} + 2O_{2(g)} \xrightarrow{\Delta} CO_{2(g)} + 2H_2O_{(l)}$
$d.$ Disproportionation reaction	$(iv)$ $2H_2O_{(l)} \xrightarrow{\text{electrolysis}} 2H_{2(g)} + O_{2(g)}$

Choose the correct answer from the options given below.