In the equation $H_2S + 2HNO_3 \to 2H_2O + 2NO_2 + S$,the equivalent weight of hydrogen sulphide is:

Number of moles of $MnO_4^-$ required to oxidize one mole of ferrous oxalate completely in acidic medium will be .......... $moles$.

Justify that the reaction: $2 Na ( s ) + H_2 ( g ) \rightarrow 2 NaH ( s )$ is a redox change.

Which of the following is a redox reaction?

Permanganate $(VII)$ ion,$MnO_4^-$,in basic solution oxidises iodide ion,$I^-$,to produce molecular iodine $(I_2)$ and manganese $(IV)$ oxide $(MnO_2)$. Write a balanced ionic equation to represent this redox reaction.

The product of $I^-$ with $MnO_4^-$ in acidic medium is