Question:
The incorrect statement among the following is :-
Correct Option: 4,
Solution:
(i) In $\mathrm{VOSO}_{4}$, ' $\mathrm{V}$ ' is in $+4$ oxidation state. So it act as oxidising agent.
(ii) $\mathrm{Cr}_{2} \mathrm{O}_{3}$ is an amphoteric oxide.
(iii) In $\mathrm{RuO}_{4}$, ' $\mathrm{Ru}$ ' is in $+8$ oxidation state.
So it act as oxidising agent.
(iv) Red colour of ruby is due to the presence of $\mathrm{Cr}^{+3}$ ions in $\mathrm{Al}_{2} \mathrm{O}_{3}$.