In basic first aid for everyday science, which of the following solutions is commonly used to treat a bee sting in order to neutralise the acidic venom and reduce pain?

Introduction / Context:
This question tests very practical science knowledge connected with first aid. Bee stings are common, and knowing the basic chemistry behind treating them helps in both real life and exam situations. Understanding whether the sting is acidic or alkaline allows you to choose the right neutralising agent among household substances.

Given Data / Assumptions:
- The pain is caused by a bee sting, not a wasp sting.
- Bee venom is mildly acidic in nature.
- The options list kitchen items such as lemon juice, milk, vinegar, baking soda solution, and salt water.
- The question mentions neutralising the venom and reducing pain, which hints at an acid base reaction.

Concept / Approach:
Bee venom contains acids such as formic acid. To reduce the effect, a mild alkali can be applied to the affected area. Baking soda, also known as sodium hydrogen carbonate, is a weak base that can neutralise the acid. In contrast, lemon juice and vinegar are acidic liquids, which would not be suitable for neutralising another acid. Milk and salt water do not specifically neutralise the toxin.

Step-by-Step Solution:
Step 1: Recall from school chemistry that acids can be neutralised by bases and vice versa. Step 2: Remember that the sting of a bee is generally treated as acidic, so a basic or alkaline substance is needed to counter it. Step 3: Identify which option is basic. Baking soda solution is alkaline, while lemon juice and vinegar are acidic, and milk and salt water are close to neutral. Step 4: Therefore, a paste or solution of baking soda applied to the sting area helps neutralise the acid and gives relief from pain. Step 5: Conclude that baking soda solution is the correct answer.

Verification / Alternative Check:
Another quick check is to recall standard first aid tips. Textbooks and health guides often say bee stings can be soothed with a weak baking soda paste, whereas wasp stings, which are more alkaline, may be treated with acidic substances like vinegar. Linking that rule of thumb with the nature of bee venom confirms that baking soda is the appropriate choice in this question.

Why Other Options Are Wrong:
Lemon juice is acidic because it contains citric acid, so it does not neutralise acidic bee venom and may even increase irritation.
Milk is nearly neutral and is not mentioned as an effective neutralising agent for bee stings in basic science references.
Vinegar is also acidic due to acetic acid, and thus is usually suggested for wasp stings, not bee stings.
Salt water has no special neutralising property for this purpose and mainly cleans the skin rather than reacting with the venom.

Common Pitfalls:
Candidates sometimes mix up bee and wasp stings and reverse the correct treatments. Another common mistake is to guess any kitchen liquid that feels soothing without thinking about acid base chemistry. To avoid such confusion, remember one simple rule: bee sting is treated with baking soda solution, while wasp sting is treated with a mild acid such as vinegar or lemon juice.

Final Answer:
The correct answer is Baking soda solution, which helps neutralise the acidic venom of a bee sting and relieve pain.