Increasing order of oxidation states of transition metal oxides will be:

(A) TiO₂

(B) MnO-₄

(C) VO₂⁺

(D) CrO₄²⁻

(E) Ni (CO)₄

Choose the correct answer from the options given below:

Question

Increasing order of oxidation states of transition metal oxides will be: (A) TiO₂ (B) MnO-₄ (C) VO₂⁺ (D) CrO₄&sup2;⁻ (E) Ni (CO)₄ Choose the correct answer from the options given below:

Prepp Team · Accepted Answer

Understanding Oxidation States in Transition Metal Compounds

To determine the increasing order of oxidation states for the given transition metal oxides and compounds, we first need to calculate the oxidation state of the transition metal in each species. The oxidation state represents the hypothetical charge an atom would have if all bonds were 100% ionic.

We will calculate the oxidation state for each option:

Calculating Oxidation States

(A) TiO2
In TiO2, oxygen typically has an oxidation state of -2. The compound is neutral overall. Let the oxidation state of Titanium (Ti) be \(x\).

The equation is: \(x + 2(-2) = 0\)

\(x - 4 = 0\)

\(x = +4\)

The oxidation state of Ti in TiO2 is +4.
(B) MnO4-
In MnO4-, oxygen has an oxidation state of -2, and the overall charge of the ion is -1. Let the oxidation state of Manganese (Mn) be \(x\).

The equation is: \(x + 4(-2) = -1\)

\(x - 8 = -1\)

\(x = -1 + 8\)

\(x = +7\)

The oxidation state of Mn in MnO4- is +7.
(C) VO2+
In VO2+, oxygen has an oxidation state of -2, and the overall charge of the ion is +1. Let the oxidation state of Vanadium (V) be \(x\).

The equation is: \(x + 2(-2) = +1\)

\(x - 4 = +1\)

\(x = +1 + 4\)

\(x = +5\)

The oxidation state of V in VO2+ is +5.
(D) CrO42-
In CrO42-, oxygen has an oxidation state of -2, and the overall charge of the ion is -2. Let the oxidation state of Chromium (Cr) be \(x\).

The equation is: \(x + 4(-2) = -2\)

\(x - 8 = -2\)

\(x = -2 + 8\)

\(x = +6\)

The oxidation state of Cr in CrO42- is +6.
(E) Ni (CO)4
In Ni(CO)4, Carbon Monoxide (CO) is a neutral ligand. Neutral ligands have an oxidation state of 0. The compound is neutral overall. Let the oxidation state of Nickel (Ni) be \(x\).

The equation is: \(x + 4(0) = 0\)

\(x + 0 = 0\)

\(x = 0\)

The oxidation state of Ni in Ni(CO)4 is 0.

Summary of Oxidation States

Species	Transition Metal	Oxidation State
(A) TiO<sub>2</sub>	Ti	+4
(B) MnO<sub>4</sub><sup>-</sup>	Mn	+7
(C) VO<sub>2</sub><sup>+</sup>	V	+5
(D) CrO<sub>4</sub><sup>2-</sup>	Cr	+6
(E) Ni (CO)<sub>4</sub>	Ni	0

Arranging in Increasing Order

Now, let's arrange the species based on the calculated oxidation states in increasing order:

Oxidation States: 0, +4, +5, +6, +7

Corresponding Species: Ni(CO)4, TiO2, VO2+, CrO42-, MnO4-

Using the letters assigned in the question:

(E) < (A) < (C) < (D) < (B)

Revision Table: Key Concepts

Concept	Description	Example
Oxidation State	Hypothetical charge on an atom in a compound/ion, assuming ionic bonding.	In H<sub>2</sub>O, oxidation state of O is -2, H is +1.
Rules for Oxidation States	Sum of oxidation states in a neutral compound is 0. Sum of oxidation states in an ion equals the charge of the ion. Oxygen is usually -2 (except in peroxides, etc.). Hydrogen is usually +1 (except in metal hydrides). Group 1 metals are +1, Group 2 are +2.	MnO<sub>4</sub><sup>-</sup> sum = -1.
Neutral Ligand	A molecule or ion that forms a coordinate bond with a central metal atom or ion and has a net charge of zero.	CO (Carbon Monoxide), NH<sub>3</sub> (Ammonia), H<sub>2</sub>O (Water).

Additional Information: Transition Metals and Oxidation States

Transition metals are known for exhibiting a wide range of oxidation states in their compounds. This is due to the involvement of both \(ns\) and \((n-1)d\) electrons in bonding. For example, Manganese (Mn) shows oxidation states from +2 (in MnO) up to +7 (in MnO4-). Lower oxidation states are often found in compounds with ligands like CO (forming metal carbonyls), while higher oxidation states are typically observed with highly electronegative elements like oxygen and fluorine. The stability of different oxidation states varies across the transition series and depends on the nature of the ligands or counterions present.