Oxidation States | MCQs

Explanation

In NH₄⁺, nitrogen has an oxidation state of –3 (typical for ammonia-like groups).

In NO₃⁻, nitrogen has an oxidation state of +5 due to its bonding with three oxygen atoms.

Explanation

In HNO₃ (nitric acid):

Hydrogen (H) = +1

Oxygen (O) = -2 (×3 = -6)

Let nitrogen = x

So, +1 + x + (−6) = 0

⇒ x = +5

Nitrogen has an oxidation state of +5 in HNO₃.

Explanation

Of the elements listed, aluminum is the one that most commonly exhibits a +3 oxidation state.

Sodium typically shows a +1 oxidation state, and magnesium typically shows a +2 oxidation state.

While iron can exist in a +3 oxidation state (as in iron(III) chloride),

It also commonly exists in a +2 oxidation state (as in iron(II) sulfate), making it a transition metal with variable oxidation states. 

Explanation

 The element that has the same oxidation number in all its compounds is Fluorine. 

Fluorine is the most electronegative element, so it always has an oxidation number of -1 in all its compounds

Explanation

Manganese (Mn) shows a maximum oxidation state of +7, as seen in compounds like KMnO₄ (potassium permanganate).

This is higher than the maximum oxidation states of Cr (+6), P (+5), and S (+6).

Explanation

The reaction 2KMnO₄ + Cl₂ → 2KMnO₄ + 2KCl is  Oxidation reduction reaction. 

In this reaction, the oxidation number of chlorine changes from 0 in Cl₂ to -1 in KCl, which is considered reduction.

While the oxidation state of manganese and potassium remains the same in KMnO₄,

The overall reaction involves a transfer of electrons between chlorine and potassium, making it a redox reaction. 

Explanation

The coordination number and oxidation state of cobalt in the given complex Na4[Co(C2O4)3] are respectively 6 and +3.