Question

Which of these chemicals are considered as insecticides?
A. DDT
B. 2, 4, D
C. Atrazine
D. Paraquat

• A. A, B and D only
• B. A, C and D only
• C. A only
• D. B and D only

Hint:

Be careful to distinguish the targets of agricultural chemicals:
- DDT = Insecticide (Organochlorine).
- 2,4-D, Atrazine, Paraquat = Herbicides (Weed killers).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Pesticides are chemical substances used to control, repel, or destroy pests, classified based on their target pest into insecticides, herbicides, fungicides, and rodenticides.

Step 2: Detailed Explanation:
Let us categorize each of the listed chemicals:
- A. DDT (Dichlorodiphenyltrichloroethane): A synthetic organochlorine chemical developed to kill insects by opening sodium channels in their nerve cells.
Thus, it is an insecticide.
- B. 2,4-D (2,4-Dichlorophenoxyacetic acid): A common systemic herbicide used to control broadleaf weeds.
Thus, it is a herbicide.
- C. Atrazine: A widely used triazine herbicide that inhibits photosynthesis, used to control broadleaf and grassy weeds in crops like corn.
Thus, it is a herbicide.
- D. Paraquat: A highly toxic, non-selective contact bipyridylium herbicide used for weed control.
Thus, it is a herbicide.

Step 3: Final Answer:
Since only DDT is an insecticide, the correct option is (C).