Question: Polyhalogen compounds have wide application in industries and agriculture. DDT is also a very important polyhalogen compound. It is a :

Step 1 (Definition and Identification): [0.5 Mark]
DDT stands for p,p'-dichlorodiphenyltrichloroethane. Chemically, it is a polyhalogenated organic compound. According to NCERT Chemistry (Class 12, Haloalkanes and Haloarenes), DDT was the first chlorinated organic insecticide. Its chemical structure is represented as:

$$ (ClC_6H_4)_2CHCCl_3 $$

Step 2 (Analysis of Properties): [0.25 Mark]
DDT is highly effective against mosquitoes and other insects. However, due to its stable chemical structure (presence of multiple $C-Cl$ bonds), it is not easily metabolized by microorganisms. Consequently, it persists in the environment for a long duration, leading to bioaccumulation in the food chain. This classifies it as a non-biodegradable substance.

Step 3 (Final Concluded Answer): [0.25 Mark]
Based on the chemical properties and environmental impact, DDT is a non-biodegradable insecticide.
Correct Option: (D)

💡 EL10 Concept Insight: Think of DDT like a plastic bottle that never rots; because it is so chemically stable, nature's tiny decomposers (bacteria) can't break it down, which is why it stays in the environment for a very long time instead of disappearing.