$SnCl_2$ gives a precipitate with a solution of $HgCl_2$. In this process $HgCl_2$ is

Which of the following changes involves the transfer of $5$ electrons?

When an acidified solution of ferrous ammonium sulphate is treated with potassium permanganate solution,the ion which is oxidised is

In the reactions given below,identify the species undergoing oxidation and reduction:
$(i)$ $H_{2}S_{(g)} + Cl_{2(g)} \rightarrow 2HCl_{(g)} + S_{(s)}$
$(ii)$ $3Fe_{3}O_{4(s)} + 8Al_{(s)} \rightarrow 9Fe_{(s)} + 4Al_{2}O_{3(s)}$
$(iii)$ $2Na_{(s)} + H_{2(g)} \rightarrow 2NaH_{(s)}$

Explain redox reactions on the basis of electron transfer. Give suitable examples.

Observe the following reaction:
$2 KClO_{3(s)} \xrightarrow{\Delta} 2 KCl_{(s)} + 3 O_{2(g)}$
In this reaction: