Question:
The incorrect statement(s) among (a) - (c) is (are) :-
(a) W(VI) is more stable than $\mathrm{Cr}(\mathrm{VI})$.
(b) in the presence of $\mathrm{HCl}$, permanganate titrations provide satisfactory results.
(c) some lanthanoid oxides can be used as phosphors.
Correct Option: , 4
Solution:
$\mathrm{KMnO}_{4}$ will not give satisfactory result when it is titrated by $\mathrm{HCl}$.