Match List I with List II

Choose the correct answer from the options given below:

A-III, B-I, C-IV, D-II

The correct answer is option 3. A-III, B-I, C-IV, D-II.

A. Oxidation state of \(MnO_2\): III. +4:

In manganese dioxide (\(MnO_2\)), oxygen is more electronegative than manganese. Oxygen typically takes on an oxidation state of \(-2\) in compounds. Since there are two oxygen atoms in \(MnO_2\), the total oxidation state contributed by oxygen is \(2 \times (-2) = -4\).

Now, the overall charge of \(MnO_2\) is neutral because it's not an ion. Therefore, the oxidation states of all the elements in the compound should add up to zero.

Let's denote the oxidation state of manganese as \(x\). To balance out the -4 charge from the oxygen atoms, the oxidation state of manganese must be such that:

\[x + (-4) = 0\]

Solving for \(x\), we find that \(x = +4\). This indicates that manganese in \(MnO_2\) has an oxidation state of +4.

B. Most stable oxidation state of \(Mn\) is : I. +2:

The +2 oxidation state is the most stable for manganese in many common compounds and chemical environments due to its electronic configuration and the nature of its chemical bonding.

Manganese, like other transition metals, can lose electrons to form positively charged ions. In the case of manganese, when it loses two electrons, it achieves a stable electronic configuration similar to the noble gas argon. Specifically, it loses its outermost 4s electrons, leaving behind a half-filled 3d orbital. This stable configuration is energetically favorable, making the +2 oxidation state relatively stable for manganese.

In aqueous solutions and many compounds, manganese tends to form manganese(II) ions, denoted as \(Mn^{2+}\). These ions commonly occur in compounds such as manganese(II) sulphate (\(MnSO_4\)) or manganese(II) chloride (\(MnCl_2\)). In these compounds, manganese is typically surrounded by ligands, such as water molecules or chloride ions, which stabilize the \(Mn^{2+}\) oxidation state.

Additionally, the +2 oxidation state is favored in manganese compounds due to the electronegativity of the elements it typically bonds with. For example, in manganese dioxide (\(MnO_2\)), where manganese exhibits a +4 oxidation state, oxygen is more electronegative and draws electron density away from manganese, making the +2 oxidation state less favorable.

Overall, the +2 oxidation state is the most stable for manganese in many common compounds and chemical environments, primarily due to its electronic configuration and the nature of its chemical bonding.

C. Most stable oxidation state of \(Mn\) in \(MnO_4^-\): IV. +7:

In the permanganate ion (\(MnO_4^-\)), manganese exhibits an oxidation state of +7.

Each oxygen atom in the permanganate ion has an oxidation state of \(-2\). Since there are four oxygen atoms, the total oxidation state contributed by oxygen is \(4 \times (-2) = -8\).

For the permanganate ion (\(MnO_4^-\)) to be electrically neutral, the sum of the oxidation states of manganese and oxygen must add up to the ion's charge of -1.

Let us denote the oxidation state of manganese as \(x\).

\(x + (-8) = -1\)

Solving for \(x\), we find that \(x = +7\).

So, the most stable oxidation state of manganese in the permanganate ion (\(MnO_4^-\)) is indeed +7.

D. Characteristic oxidation state of lanthanoids is:  II. +3:

Lanthanoids, also known as lanthanides, are a group of elements in the periodic table that includes elements from atomic number 57 (lanthanum, La) to 71 (lutetium, Lu). One of the defining characteristics of lanthanoids is their tendency to exhibit a characteristic oxidation state of +3 in their chemical compounds.

The +3 oxidation state arises from the electronic configuration of lanthanoid elements. Lanthanoid atoms have partially filled 4f orbitals, which are typically involved in chemical bonding. When lanthanoid atoms lose three electrons, they achieve a stable configuration where the 4f orbitals are partially filled. This stable configuration corresponds to the +3 oxidation state.

In most of their chemical compounds, lanthanoids prefer to exhibit the +3 oxidation state due to the stability associated with the partially filled 4f subshell. This means that in a majority of lanthanoid compounds, the lanthanoid atom will have an oxidation state of +3.

While lanthanoids can sometimes exhibit other oxidation states under specific conditions or in certain compounds, such as +2 or +4, the +3 oxidation state is by far the most common and characteristic for these elements across their various compounds and chemical environments.