The sediment that accumulates at the bottom of lead acid battery, largely consists of:

Explanation:

Sediment Accumulation in Lead Acid Batteries

Definition: In lead-acid batteries, sediment accumulation refers to the buildup of solid material at the bottom of the battery cells over time. This sediment primarily consists of disintegrated active material from the battery plates, which can affect the battery's performance and lifespan if not managed properly.

Composition of Sediment: The sediment in lead-acid batteries is largely made up of lead compounds that have fallen off from the plates during the charge and discharge cycles. However, it is important to identify the specific types of lead compounds that make up this sediment to understand its impact and manage it effectively.

Correct Option Analysis:

The correct option is:

Option 3: Antimony lead alloy

This option is correct because the sediment that accumulates at the bottom of lead-acid batteries often contains antimony lead alloy. Antimony is commonly added to the lead in battery plates to enhance their mechanical strength and resistance to corrosion. Over time, small particles of this alloy can break off and settle at the bottom of the battery. This sediment can affect the battery's performance by potentially causing short circuits between the plates if it builds up excessively.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: Lead peroxide

Lead peroxide (PbO₂) is an active material used in the positive plates of lead-acid batteries. While it can contribute to the sediment, it is not the primary component. Lead peroxide can degrade into other compounds, which may then become part of the sediment, but it is not the main constituent of the sediment that accumulates at the bottom of the battery.

Option 2: Lead sulphate

Lead sulphate (PbSO₄) forms on both the positive and negative plates during the discharge cycle of a lead-acid battery. While lead sulphate can contribute to the sediment, especially if the battery is not properly maintained and undergoes excessive cycling, it is not the primary component. Lead sulphate can dissolve back into the electrolyte during the recharge cycle, reducing its presence in the sediment.

Option 4: Graphite

Graphite is not typically found in lead-acid batteries. It is not used in the construction of the plates or other components of the battery. Therefore, graphite is not a constituent of the sediment that accumulates at the bottom of lead-acid batteries.

Conclusion:

Understanding the composition of the sediment in lead-acid batteries is crucial for maintaining their performance and longevity. The correct answer, antimony lead alloy, highlights the importance of additives in the battery plates and their potential impact on sediment formation. Proper maintenance and periodic inspection of the sediment can help prevent performance issues and extend the life of the battery.