Ethanoic acid is also known as.A) Citric acid.B) Nitric acid.C) Acetic acid.D) Formic acid.

Ethanoic acid is commonly known as **Acetic acid**.

Here’s an explanation:

- **Ethanoic acid** is a carboxylic acid with the formula \( \text{CH}_3\text{COOH} \).
- **Acetic acid** is the common name for this compound. It is a key component of vinegar, which typically contains about 4-8% acetic acid by volume.

Let's briefly go over the other options:

- **Citric acid** is a different carboxylic acid with the formula \( \text{C}_6\text{H}_8\text{O}_7 \). It is found in citrus fruits and used as a preservative and flavoring agent.
- **Nitric acid** is a strong mineral acid with the formula \( \text{HNO}_3 \), not related to acetic acid.
- **Formic acid** is another carboxylic acid, but with the formula \( \text{HCOOH} \). It is the simplest carboxylic acid and is found in the stings of ants and bees.

So, the correct answer is **C) Acetic acid**.