$Na_2S_2O_3 \cdot 5H_2O$ is used in photography to

Which of the following can chlorine not displace?

The reaction of concentrated $HNO_3$ with iodine produces ....

Consider the following reactions:
$(A) (\text{Ionic halide}) + (B) (\text{Good oxidising agent}) + \text{conc. } H_2SO_4 \to (C) (\text{Red-Orange gas is evolved with few by-products})$
$(D) (\text{Other ionic halide}) + (B) + \text{conc. } H_2SO_4 \to (E) (\text{Has same colour as } (C))$
Which of the following properties are different for $(C)$ and $(E)$?

Which of the following properties does not correspond to the order $HI < HBr < HCl < HF$?

Which one of the following halogens liberates oxygen when passed through hot concentrated $KOH$ solution?