The incorrect statement(s) among (a) - (c) is (are):

(a)$\mathrm{W}\left(\mathrm{VI}\right)$ is more stable than$\mathrm{Cr}\left(\mathrm{VI}\right)$.

(b) In the presence of $\mathrm{HCl}$, permanganate titrations provide satisfactory results.

(c) Some Lanthanoid oxides can be used as Phosphors.

The correct option is D

(b) only

The appropriate choices are: (d)

The explanation for the correct answers is:

(d)

(b) only

• Explanation: In the vicinity of $\mathrm{HCl}$, permanganate titrations produce good outcomes. Using potassium permanganate to titrate oxalates, which combines with to generate chlorine The result is $\mathrm{HCl}$ utilizes the ${\mathrm{KMnO}}_4$titrant.

The explanation for the incorrect options:

(a)

(a) only

• Explanation: This idea is supported by the fact that as we move down the periodic table from top to bottom, the stability of elements with higher oxidation states will rise.
• The fact that the longevity of elements with larger oxidation states will increase as we move from the top of the periodic table to the bottom supports this theory.

(b)

(b) and (c) only

• Explanation: Oxalates are titrated using potassium permanganate, which combines with$\mathrm{HCl}$ to produce chlorine. As a result, $\mathrm{HCl}$ uses up the ${\mathrm{KMnO}}_4$titrant.

(c) Some lanthanoid oxides can be used as phosphors.

• Explanation: Lanthanide oxides are helpful in luminous materials such as phosphors. A useful analytical oxidizing agent is ceramic sulfate. Lanthanide oxides are used in the glass, ceramic, electronics, chemical, and nuclear industries, both as natural-ratio mixed oxides and as high-purity compounds

(c)

(a) and (b) only

• Explanation: The fact that the longevity of elements with larger oxidation states will increase as we move from the top of the periodic table to the bottom supports this theory. Lanthanide oxides are used in the glass, ceramic, electronics, chemical, and nuclear industries, both as natural-ratio mixed oxides and as high-purity compounds.

(b) In the presence of$\mathrm{HCl}$, permanganate titrations provide satisfactory results.

• Explanation: Oxalates are titrated using potassium permanganate, which combines with$\mathrm{HCl}$ to produce chlorine. which combines with to generate chlorine The result utilizes the ${\mathrm{KMnO}}_4$titrant.

The final correct answer is (d): it will not give satisfactory results when it is titrated by$\mathrm{HCl}$.