Which of the following organic acids is present in the sting of red ants and responsible for the burning sensation?

Introduction / Context:
When a red ant stings, you feel a sharp burning and itching sensation on the skin. This reaction is caused by a chemical substance injected by the ant as a defensive mechanism. General science questions often ask which acid is responsible for this sensation. Knowing the names and sources of common organic acids, such as acetic acid in vinegar or citric acid in lemons, helps you answer such everyday application questions easily.

Given Data / Assumptions:
– The question focuses on red ants and the acid present in their sting.
– Options list Malic acid, Formic acid, Tannic acid, and Oxalic acid.
– We assume a basic understanding that different acids occur naturally in fruits, plants, and animal secretions.
– The task is to identify which specific acid is characteristic of ant stings.

Concept / Approach:
Formic acid is the simplest carboxylic acid and is historically associated with ants. In fact, the word formic comes from the Latin word for ant, formica. Many ant species, including red ants, produce formic acid in their venom glands and inject it into the skin when they sting. This acid causes the burning sensation and mild inflammation at the sting site. Malic acid is commonly found in apples and some other fruits. Tannic acid occurs in tea and certain plant materials and is associated with astringency. Oxalic acid is present in plants like spinach and rhubarb and is also known for forming insoluble salts with calcium. None of these other acids are the typical primary component of ant venom.

Step-by-Step Solution:
Step 1: Recall that the term formic acid historically comes from the study of ants and their chemical secretions. Step 2: Remember that red ant stings are specifically known to contain formic acid, which causes irritation and burning. Step 3: Recognise that malic acid and tannic acid are more associated with fruits and tea, not with animal stings. Step 4: Conclude that formic acid is the correct acid present in red ant stings.

Verification / Alternative check:
You can verify this fact by consulting a chemistry or biology reference, which will often mention formic acid in sections about organic acids or animal venoms. Ant species, especially those in the Formicidae family, are noted for producing formic acid as a defense chemical. Historical chemistry experiments even obtained formic acid by distilling crushed ants. In contrast, discussions about malic, tannic, and oxalic acids focus on plant sources and do not connect them with ant stings. This pattern of evidence supports formic acid as the correct answer.

Why Other Options Are Wrong:
Malic acid: This acid is found mainly in apples and some other fruits and is responsible for a sour taste, not for ant stings.
Tannic acid: Commonly associated with tea, bark, and other plant materials, tannic acid is related to astringent taste and is not the active chemical in ant venom.
Oxalic acid: Present in plants such as spinach and rhubarb, oxalic acid can form crystals with calcium but is not the primary irritant used by red ants in their stings.

Common Pitfalls:
A frequent error is to choose an acid that sounds more familiar, like malic or oxalic acid, without recalling the specific connection between ants and formic acid. Another problem is not paying attention to the origin of the word formic, which directly hints at ants. To avoid such mistakes, try to build simple associations: formic acid with ants, acetic acid with vinegar, citric acid with citrus fruits, and lactic acid with muscles and sour milk. These memory hooks make recall much easier during exams.

Final Answer:
The organic acid present in the sting of red ants that causes the burning sensation is Formic acid.