Compound A used as a strong oxidising agent is amphoteric in nature. It is the part of lead storage

Q: What exactly is the inert pair effect?

The inert pair effect is the tendency of the outermost s-orbital electrons in heavier p-block elements (like Lead, Bismuth, and Thallium) to remain unshared in compounds. This makes their lower oxidation state (e.g., +2 for Lead) more stable than their higher oxidation state (+4).

Q: Why does PbO2 act as a strong oxidising agent?

In PbO2, lead is in the +4 oxidation state. Due to the inert pair effect, the +2 state is much more stable. Therefore, Pb(IV) strongly desires to gain two electrons to become Pb(II), thereby oxidising other substances in the process.

Q: What is the composition of Pb3O4?

Pb3O4, also known as red lead or minium, is actually a mixed oxide. It can be thought of as 2PbO·PbO2, meaning it contains lead in both the +2 and +4 oxidation states.

Q: How does PbO2 demonstrate its amphoteric nature?

An amphoteric substance can react with both acids and bases. PbO2 reacts with acids (like HCl) to form lead salts, and it reacts with strong bases (like NaOH) to form plumbate compounds (like Na2PbO3).

Q: What happens at the cathode of a lead storage battery during discharge?

During discharge, the PbO2 at the cathode is reduced. It reacts with sulfate ions and hydrogen ions from the sulfuric acid electrolyte to form solid lead sulfate (PbSO4) and water.

Question

Compound A used as a strong oxidising agent is amphoteric in nature. It is the part of lead storage batteries. Compound A is

Options:

(A) $	ext{PbO}_2$

(B) $	ext{PbO}$

(C) $	ext{PbSO}_4$

(D) $	ext{Pb}_3	ext{O}_4$

Sigma Percentile · Accepted Answer

### Decoding the Chemical Clues

When a chemistry problem presents you with a set of specific properties, it's like a puzzle waiting to be solved. In this question, we are looking for a compound of lead that satisfies three distinct conditions: it must be a **strong oxidising agent**, it must be **amphoteric**, and it must be a component of **lead storage batteries**.

Let's break down these clues one by one to identify the mystery compound.

### The Inert Pair Effect and Oxidising Power

Lead ($Pb$) is a heavy metal located in Group 14 of the periodic table. Elements in this group typically exhibit $+2$ and $+4$ oxidation states. However, as we move down the group, the $+2$ oxidation state becomes increasingly stable compared to the $+4$ state. This phenomenon is known as the **inert pair effect**, where the outermost $s$-electrons are reluctant to participate in bonding.

Because $Pb^{2+}$ is much more stable than $Pb^{4+}$, any compound containing lead in the $+4$ oxidation state will have a strong tendency to gain two electrons and reduce to the $+2$ state.

$$Pb^{4+} + 2e^- \rightarrow Pb^{2+}$$

This spontaneous reduction ($\Delta G^\circ < 0$) makes $Pb(IV)$ compounds excellent **oxidising agents**. Looking at our options, $PbO_2$ contains lead in the $+4$ state, making it a prime candidate.

### The Lead Storage Battery

Next, let's consider the practical application mentioned: the lead storage battery. This is the standard rechargeable battery used in automobiles.

In a fully charged lead storage battery:
- The **anode** is made of spongy lead ($Pb$).
- The **cathode** consists of a lead grid packed with **lead dioxide ($PbO_2$)**.

During discharge, both electrodes react with sulfuric acid to form lead sulfate ($PbSO_4$). The presence of $PbO_2$ at the cathode perfectly aligns with our second clue.

### Verifying the Amphoteric Nature

Finally, we must confirm that $PbO_2$ is amphoteric, meaning it can react with both acids and bases.

When $PbO_2$ reacts with a strong acid like hydrochloric acid, it acts as a base (and an oxidising agent):
$$PbO_2 + 4HCl \rightarrow PbCl_2 + Cl_2 + 2H_2O$$

Conversely, when it reacts with a strong base like sodium hydroxide, it acts as an acidic oxide, forming a soluble plumbate salt:
$$PbO_2 + 2NaOH \rightarrow Na_2PbO_3 + H_2O$$

Since $PbO_2$ satisfies all three conditions—it is a strong oxidising agent, it is amphoteric, and it is used in lead storage batteries—we can confidently conclude that Compound A is **lead dioxide ($PbO_2$)**.

Animated Solution for Chemistry - Electrochemistry: Compound A used as a strong oxidising agent is amphoteric in nature. It is the part of lead storage batteries. Compound A is

Select Answer:

Visualized Solution

$Decoding the Clues$

$Oxidation States of Lead$

$Oxidising Nature$

$Lead Storage Battery$

$Amphoteric Nature of PbO_{2}$

$Conclusion$

The Sigma Insight: Electrochemical Cells

Decoding the Chemical Clues

The Inert Pair Effect and Oxidising Power

The Lead Storage Battery

Verifying the Amphoteric Nature

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