In common household chemistry, which of the following substances is the everyday name for dilute acetic acid used in cooking and food preservation?

Introduction / Context:
This question builds a bridge between basic organic chemistry and everyday life by asking you to identify the common name for dilute acetic acid. In kitchens around the world, people frequently use a sour liquid called vinegar for cooking, pickling, and cleaning. Chemically, this liquid is nothing but acetic acid dissolved in water at a relatively low concentration. Understanding this link reinforces your ability to recognize the chemical nature of familiar household substances and helps you see how textbook concepts about acids appear in practical contexts.

Given Data / Assumptions:
- The chemical substance of interest is dilute acetic acid, an organic carboxylic acid solution.
- You must identify which everyday material corresponds to this dilute acetic acid.

Concept / Approach:
The key concept is that vinegar is a dilute aqueous solution of acetic acid, usually containing about four to eight percent acetic acid by volume. The rest of the solution is water. Baking soda is sodium bicarbonate, a basic compound rather than an acid. Copper sulphate and magnesium oxide are inorganic salts and oxides used for other purposes and have very different properties from acetic acid. Therefore, by matching the chemical name acetic acid with the culinary and household product known as vinegar, you can easily determine the correct answer.

Step-by-Step Solution:
Step 1: Recall that vinegar is a sour liquid widely used for cooking, pickling, and cleaning, and that it is known chemically as dilute acetic acid. Step 2: Remember that acetic acid has the formula CH3COOH and belongs to the carboxylic acid family. Step 3: Compare the options. Baking soda is sodium bicarbonate, NaHCO3, and behaves as a mild base in water. Step 4: Note that copper sulphate, CuSO4, is a blue salt often used in laboratories and agriculture, and magnesium oxide is a basic oxide used in industrial and medicinal settings. Step 5: Conclude that none of these match dilute acetic acid except vinegar, which is the common name for that solution, so Vinegar is correct.

Verification / Alternative check:
You can verify this by reading labels on commercial vinegar bottles, which commonly specify acetic acid content as a percentage. Chemistry textbooks and food science references likewise define vinegar as a dilute solution of acetic acid in water. Meanwhile, descriptions of baking soda clearly identify it as sodium bicarbonate, and the formulae of copper sulphate and magnesium oxide confirm that they are not carboxylic acids. This consistent agreement between real world packaging and scientific literature confirms that vinegar is the everyday name for dilute acetic acid.

Why Other Options Are Wrong:
Baking soda is a basic salt, not an acid, and is used for baking and cleaning but does not correspond to acetic acid. Copper sulphate is a blue crystalline salt primarily used as a fungicide, algicide, or laboratory reagent and is not related to the culinary use of vinegar. Magnesium oxide is a white basic oxide used in refractory materials and some medicines. None of these substances are dilute acetic acid or share the same common usage as vinegar, so they are incorrect matches for the chemical described in the question.

Common Pitfalls:
Students sometimes confuse baking soda with baking powder or assume that anything associated with baking must be acidic. Others may select copper sulphate or magnesium oxide simply because they recognize the chemical names without recalling their uses. Another mistake is failing to connect the word vinegar with its underlying chemical name. To avoid these errors, remember that vinegar is sour and acidic due to acetic acid, whereas baking soda is mild and basic and copper sulphate and magnesium oxide are used in completely different contexts.

Final Answer:
The everyday substance that is essentially dilute acetic acid is Vinegar.