Vanadium pentachloride undergoes hydrolysis so that

The correct answer is Option (3) → The formation of VOCl₃ and HCl takes place.

Hydrolysis of a covalent halide replaces halogen atoms by oxygen (or –OH) from water and releases HCl. It is not a redox reaction, so the oxidation state of the central atom does not change. In partial hydrolysis, one oxygen atom replaces two chlorine atoms and an oxohalide is formed, as with phosphorus pentachloride:

    \( \displaystyle \ce{PCl5 + H2O -> POCl3 + 2HCl} \)

In the same way, vanadium(V) chloride would give vanadium oxotrichloride:

    \( \displaystyle \ce{VCl5 + H2O -> VOCl3 + 2HCl} \)

The oxidation state of V is unchanged: in \( \ce{VCl5} \), x + 5(−1) = 0 gives +5; in \( \ce{VOCl3} \), x + (−2) + 3(−1) = 0 also gives +5. So the products are VOCl₃ and HCl.

Why the other options are incorrect

• Option (1) The formation of VOCl₂ and HCl takes place — Incorrect. In \( \ce{VOCl2} \), x + (−2) + 2(−1) = 0 gives V = +4, which would need a reduction, not a hydrolysis.

• Option (2) The formation of VO₂Cl and HCl takes place — Incorrect. V is still +5 here, but four chlorine atoms have been replaced; this is a further stage of hydrolysis, not the first oxohalide formed.

• Option (4) The formation of VOCl and HCl takes place — Incorrect. In VOCl, x + (−2) + (−1) = 0 gives V = +3, again a change of oxidation state.

Note 1: The question is from beyond the NCERT textbook.

Note 2: It seems that there is a mistake in the original NTA paper, which prints vanadium pentachloride (VCl₅), a compound that is not known; the highest chloride of vanadium is VCl₄.