Calculate the number of moles of electrons required to convert $1.1 \mathrm{~mol} \mathrm{Cr}_2 \mathrm{O}_7^{2-}$ to $\mathrm{Cr}^{3+}$ in acidic medium.

Identify oxidant in following reaction.

$$ 3 \mathrm{H}_3 \mathrm{AsO}_{3(\mathrm{aq})}+\mathrm{BrO}_{3(\mathrm{aq})}^{-} \longrightarrow \mathrm{Br}_{(\mathrm{aq})}^{-}+3 \mathrm{H}_3 \mathrm{AsO}_{4(\mathrm{aq})} $$

Which of the following changes exhibit that nitrogen undergoes oxidation?