Which of the following is not a volatile organic ompound ?

Acetaldehyde
Formaldehyde
Hydrochloric Acid
Dichloromethane

The correct answer is (c), Hydrochloric Acid.

A volatile organic compound (VOC) is a chemical compound that has a high vapor pressure at ordinary temperatures. VOCs are often found in gasoline, paints, and other household products. They can be released into the air through evaporation, combustion, or other processes.

Acetaldehyde, formaldehyde, and dichloromethane are all VOCs. They are all colorless, flammable liquids with a strong odor. Acetaldehyde is used in the production of plastics, resins, and other chemicals. Formaldehyde is used in the production of building materials, adhesives, and other products. Dichloromethane is used as a solvent and in the production of refrigerants and other chemicals.

Hydrochloric acid is a strong acid that is not a VOC. It is a colorless, fuming liquid with a strong odor. Hydrochloric acid is used in the production of chemicals, pharmaceuticals, and other products. It is also used in metal etching and cleaning.

VOCs can be harmful to human health. They can cause respiratory problems, cancer, and other health problems. VOCs can also contribute to air pollution.