Chemistry Miscellaneous Part-1

11. An active chemical to remove mosquitoes is: [41st B.P.S.C. (Pre) 1996]

(a) Allethrin
(b) Atropin
(c) 2-ISO propoxiphinyal
(d) Benzene Hexachlorophene

Correct Answer: (a) Allethrin

Solution:Allethrin is a pyrethroid synthesized insecticide/pesticide and is an active chemical used to remove mosquitoes.

12. Prallethrin is a common: [U.P. P.C.S. (Mains) 2017]

(a) Analgesic
(b) Muscle relaxant
(c) Mosquito repellent
(d) Hair dye

Correct Answer: (c) Mosquito repellent

Solution:Prallethrin is a pyrethroid insecticide, used in liquid vaporizers as a repellent against mosquitoes.

13. Which of the following is used as a mosquito repellent? [U.P.P.C.S. (Mains) 2009]

(a) Pyrethrum
(b) Rotenone
(c) Ephedrine
(d) None of the above

Correct Answer: (a) Pyrethrum

Solution:Pyrethrum is a natural botanical insecticide with potent insecticidal activity by targeting the nervous system of mosquitoes.

14. Pyrethrin used in mosquito coils is obtained from: [U.P.P.C.S. (Pre) 2005]

(a) A seed plant
(b) An insect
(c) A bacterium
(d) A fungus

Correct Answer: (a) A seed plant

Solution:Pyrethrins are a class of organic compounds derived from Chrysanthemum cinerariifolium, a seed plant.

15. Which one of the following is used in preparing a natural mosquito repellent? [I.A.S. (Pre) 2021]

(a) Congress grass
(b) Elephant grass
(c) Lemongrass
(d) Nut grass

Correct Answer: (c) Lemongrass

Solution:Lemongrass, also known as citronella grass or fever grass, is a genus of Asian, African, Australian, and tropical island plants in the grass family. It is used for the production of citronella oil, which is used in soaps, as an insect repellent (especially for mosquitoes and houseflies), in insect sprays and candles, and in aromatherapy. It is known to be an excellent mosquito repellent. Around 95% of mosquitoes from a specific range of species are either killed or completely repelled due to the intense odour of lemongrass oil.

16. Which chemical substance is used for making rat poison? [47th B.P.S.C. (Pre) 2005]

(a) Ethyl Alcohol
(b) Methyl Isocyanate
(c) Potassium Cyanide
(d) Ethyl Isocyanide

Correct Answer: (c) Potassium Cyanide

Solution:Potassium cyanide (KCN) and zinc phosphide are highly toxic chemicals used as rodenticides—a poison to kill the mouse.

17. Which one of the following is used as rat poison? [U.P.P.C.S. (Mains) 2012]

(a) Zinc Sulphide
(b) Lead Sulphide
(c) Calcium Phosphate
(d) Zinc Phosphide

Correct Answer: (d) Zinc Phosphide

Solution:Zinc phosphide is a common active ingredient in many rodenticides. When ingested by rodents, it reacts with stomach acid to release phosphine gas, which is highly toxic.

18. Rodenticide is the chemical which is used to control: [Uttarakhand P.C.S. (Mains) 2002]

(a) Bats
(b) Monkeys
(c) Mouse
(d) Rabbits

Correct Answer: (c) Mouse

Solution:Rodenticides are pesticides specifically designed to kill rodents, which include mice, rats, and voles.

19. Aluminium Phosphide is used as: [U.P.P.C.S. (Spl) (Mains) 2008]

Correct Answer: (e) Rodenticide & Fumigant

Solution:Aluminium Phosphide is a highly toxic inorganic compound. It is a cheap, easily available pesticide which causes lethal poisoning by liberation of phosphine gas. It is also used as a fumigant for the preservation of cereals and as a rodenticide.

20. Which of the following is an example of a herbicide? [U.P.P.C.S. (Pre) 2019]

(a) Sodium chlorate
(b) Potassium permanganate
(c) Bleaching powder
(d) None of the above

Correct Answer: (a) Sodium chlorate

Solution:Herbicides, also commonly known as weedkillers, are substances used to control unwanted plants. Sodium chlorate (NaClO₃) is an oxidizing agent and is used as a herbicide.