Question

At room temperature, formaldehyde is

• A. gas
• B. liquid
• C. solid
• D. none of these

Hint:

Formaldehyde is usually found as a gas at room temperature but is often stored as a liquid in formalin (a water-based solution).

Answer 1

The Correct Option is B

Step 1: Understanding the properties of formaldehyde.
Formaldehyde (CH₂O) is a simple organic compound. At room temperature, it is typically found in the form of a gas, but in a concentrated form (such as in formalin), it exists as a liquid.
Step 2: Room temperature state of formaldehyde.
At standard room temperature (around 25°C), formaldehyde is in a gaseous state, but when dissolved in water or in a concentrated solution, it appears as a liquid (formalin).
Step 3: Apply to the options.
Formaldehyde at room temperature is most commonly a liquid when dissolved in water, which is why option (B) is correct.
Final Answer: \[ \boxed{\text{liquid}} \]