Which of the following is a good reducing agent?

As the atomic number of halogens increases,the halogens:

What is formed when iodine dissolves readily in a solution of potassium iodide?

Aqueous solution of which of the following acids cannot be kept in a bottle of glass?

To purify fluorine gas,fumes of $HF$ are removed by

Identify $A, B, C$ and $D$ in the reactions:
$(I)$ $x Cl_2 + y NaOH \longrightarrow A + B + H_2 O_{(l)}$ (Cold,dil.)
$(II)$ $x Cl_2 + y NaOH \longrightarrow C + D + H_2 O_{(l)}$ (Hot,conc.)