Explanation:
Lead nitrate solution is a highly corrosive solution that can react with certain metals and release toxic gases. Therefore, it is important to choose a spoon made of a metal that is resistant to corrosion and does not react with the solution.

The correct answer is option B, Silver. Here's why:

1. Corrosion Resistance: Silver is highly resistant to corrosion and does not react with most chemicals, making it a good choice for stirring lead nitrate solution.

2. Stability: Silver is a stable metal and does not undergo any significant chemical changes when it comes in contact with lead nitrate solution. This ensures that the spoon does not contaminate the solution.

3. Toxicity: Unlike some other metals, silver is not toxic to humans, which means that it is safe to use as a stirring spoon.

Other options:

a) Sodium: Sodium is a highly reactive metal that reacts violently with water and can release toxic gases when it comes in contact with lead nitrate solution. Therefore, it is not a suitable choice for stirring this solution.

c) Iron: Iron is a reactive metal that can corrode in the presence of acidic solutions like lead nitrate. It can also react with the solution and release hydrogen gas, which can be dangerous. Therefore, it is not a suitable choice.

d) Aluminium: Aluminium is also a reactive metal that can corrode in the presence of acidic solutions. It can also react with lead nitrate solution and release hydrogen gas. Therefore, it is not a suitable choice.

Here sodium,iron and aluminium are high reactive compared to silver..if we use them so..then they may take part in the reaction...so silver spoon is used