​Which of the following toxic chemicals are used in electrical transformers?​

Correct option is D

Polychlorinated biphenyls (PCBs) are toxic chemicals that were widely used as insulating fluids in electrical transformers and capacitors due to their non-flammability, chemical stability, and excellent insulating properties. However, PCBs are highly toxic, persistent in the environment, and bioaccumulative, leading to severe health and ecological concerns. Because of these reasons, the use of PCBs in electrical equipment has been banned or heavily restricted in many countries since the late 1970s.

The other options are not used in transformers:

Peroxy Acetyl Nitrate is a component of photochemical smog and an air pollutant.

Atrazine is a herbicide used in agriculture.

Perfluorooctane sulfonate (PFOS) is used in stain repellents and firefighting foams, not in transformers.

Hence, the correct answer is Polychlorinated biphenyls (PCBs).

Information Booster:

PCBs were used in transformers, capacitors, and other electrical equipment for their insulating and cooling properties.

PCBs are highly stable and resist degradation, causing long-term environmental contamination.

They can accumulate in the food chain, leading to toxic effects in wildlife and humans, including cancer and immune system damage.

Disposal of PCB-containing equipment requires special handling to prevent environmental release.

Alternatives such as mineral oil and silicone-based fluids have replaced PCBs in transformers.

International conventions like the Stockholm Convention aim to eliminate PCB use globally.