Chemistry Miscellaneous (Part-2)

Total Questions: 38

11. Which is used in Dry Washing? [Chhattisgarh P.C.S. (Pre) 2014]

Correct Answer: (d) All the above
Solution:Dry cleaning (often referred to as dry washing) uses solvents other than water to clean clothes. Historically, and even in some modern practices, organic solvents like petrol (naphtha), benzene, and alcohols (though less common now) were used.

The most common modern dry cleaning solvent is tetrachloroethylene (perchloroethylene), also known as "perc." However, from the given options, all listed solvents have been historically or are potentially usable in some form of dry cleaning.

12. ‘Red ink’ is prepared from [U.P.R.O./A.R.O. (Pre) 2014]

Correct Answer: (d) Eosin
Solution:Eosin is a Tetrabromofluorescein. Most red inks are dilute solution of the red dye Eosin.

13. Which one of the following colours is supplied by Sodium Chromate? [U.P. PCS (Mains) 2016]

Correct Answer: (b) Yellow
Solution:The Yellow color is supplied by Sodium Chromate Na₂CrO₄.

14. Which among the following would cause the bright red colour due to bursting of crackers? [67th B.P.S.C. (Pre) (Re. Exam) 2012]

Correct Answer: (a) Strontium
Solution:Different elements and metal compounds in firecrackers give different colors. Strontium salts are responsible for the crimson red color.

15. Match List-I with List-II and select the correct answer: [U.P.R.O./A.R.O. (Mains) 2013]

 

List-IList-II
A. Acetone1. Fire extinguisher
B. Carbon Tetrachloride2. Nail polish remover
C. Hydrogen Peroxide3. Dressing of wounds
D. Liquid Ammonia4. Refrigerant

 

Code

A

B

C

D

(a)

4

3

2

1

(b)

3

4

1

2

(c)

2

1

3

4

(d)

1

3

4

2

Correct Answer: (c)
Solution:Correctly matched pairs:
  • Acetone – Nail polish remover
  • Carbon Tetrachloride – Fire extinguisher
  • Hydrogen Peroxide – Dressing of wounds
  • Liquid Ammonia – Refrigerant

16. Which of the following pairs are not correctly matched? [U.P. Lower Sub. (Pre) 1998]

Correct Answer: (c) Hydrochloric acid – Accumulator cell
Solution:Sulphuric acid (not hydrochloric acid) is used in accumulator cells (lead-acid cells). Other pairs are correctly matched.

17. Which of the following main elements is used in making matchboxes? [U.P. Lower Sub. (Pre) 2004]

Correct Answer: (b) Phosphorous
Solution:The safety matchbox ignites due to the extreme reactivity of phosphorus with potassium chlorate on the match head. Phosphorus is a highly reactive, non-toxic chemical used in making the striking surface of a matchbox.

18. Which one of the following is used for manufacturing safety matches? [U.P. R.O./A.R.O. (Pre) 2016]

Correct Answer: (c) Red phosphorus
Solution:Red phosphorus and phosphorus trisulfide are used for manufacturing safety matches. The matchstick’s head is composed of potassium chlorate, red lead, antimony sulphide, and glue. The striking surface of matchboxes is typically composed of red phosphorus, antimony sulphide, powdered lead, and glue.

19. When kept in air and darkness, which of the following elements glows spontaneously? [U.P. P.C.S. (Mains) 2016]

Correct Answer: (b) White phosphorus
Solution:White phosphorus is a waxy, transparent solid that sublimates if exposed to light. It sublimates directly from solid to gas when heated, without changing to a liquid. White phosphorus is phosphorescent and emits a greenish-white glow.

20. Carbon Nanotubes (CNTs) were prepared by [U.P.P.C.S. (Mains) 2008]

Correct Answer: (b) Iijima
Solution:Sumio Iijima is a Japanese physicist, often cited as the inventor of carbon nanotubes.