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Chemistry (Part-XIV)

📆 May 23, 2025

Total Questions: 50

21. Who discovered Nitrogen? [S.S.C. Online CHSL (T-I) 9.01.2017 (Shift-III) ]

Correct Answer: (d) Rutherford
Solution:Daniel Rutherford, a Scottish physician and botanist, is credited with the discovery of nitrogen in 1772. He demonstrated that air contained a gas that did not support combustion or respiration, calling it "noxious air" or "phlogisticated air." This gas was later identified as nitrogen.

22. ______ is used for making vinegar. [S.S.C. Online CHSL (T-I) 15.01.2017 (Shift-III) ]

Correct Answer: (d) Acetic acid
Solution:Vinegar is essentially a dilute solution of acetic acid (CH₃COOH), typically 5-20% by volume, produced by the fermentation of ethanol (alcohol) by acetic acid bacteria. This process is commonly known as acetous fermentation.

23. What is the dominant chemical present in vinegar? [S.S.C. Online Graduate Level (T-I) 10.06.2019 (Shift-II) ]

Correct Answer: (d) Ethanoic Acid
Solution:The main acid found in vinegar is ethanoic acid. Its chemical name is acetic acid, which is used for food processing purposes. Acetic acid (CH₃COOH) is an organic acid with a pungent odor. Vinegar can be identified only by this pungent smell of acetic acid.

24. Chemical name of vinegar is : [S.S.C. Online Graduate Level (T-I) 1.09.2016 (Shift-II), S.S.C. Online C.P.O.S.I. (T-I) 5.07.2017 (Shift-II) ]

Correct Answer: (b) Acetic acid
Solution:The main acid found in vinegar is ethanoic acid. Its chemical name is acetic acid, which is used for food processing purposes. Acetic acid (CH₃COOH) is an organic acid with a pungent odor. Vinegar can be identified only by this pungent smell of acetic acid.

25. Which acid does vinegar contain? [S.S.C. Online MTS (T-I) 22.10.2021 (Shift-II) ]

Correct Answer: (d) Acetic acid
Solution:The main acid found in vinegar is ethanoic acid. Its chemical name is acetic acid, which is used for food processing purposes. Acetic acid (CH₃COOH) is an organic acid with a pungent odor. Vinegar can be identified only by this pungent smell of acetic acid.

26. Acetic acid is called ______ . [S.S.C. Online CHSL (T-I) 19.01.2017 (Shift-II) ]

Correct Answer: (d) Vinegar
Solution:The main acid found in vinegar is ethanoic acid. Its chemical name is acetic acid, which is used for food processing purposes. Acetic acid (CH₃COOH) is an organic acid with a pungent odor. Vinegar can be identified only by this pungent smell of acetic acid.

27. What is diluted acetic acid commonly known as? [S.S.C. Online Constable GD 19.02.2019 (Shift-I) ]

Correct Answer: (d) Vinegar
Solution:Dilute acetic acid is commonly known as vinegar. It is used in this form as a preservative for edible items like pickles etc. The chemical formula of acetic acid is CH₃COOH.

28. Which of the following chemical compounds is used as a preservative in pickle? [S.S.C. Online MTS (T-I) 14.08.2019 (Shift-III) ]

Correct Answer: (d) Sodium Benzoate
Solution:Sodium benzoate (C₆H₅COONa) is widely used as a preservative for foods. Pickles, tomato sauces, and fruit jams are preserved with the help of sodium benzoate to make them useful or edible for a longer period.

29. Which among the following is false about acids? [S.S.C. Online CHSL (T-I) 16.01.2017 (Shift-II) ]

Correct Answer: (d) They are bad conductor of electricity in aqueous solution
Solution:Acids remain in the ionized state in aqueous solutions, because hydrogen is the major component of most acids and in forming aqueous solutions of acids, hydrogen comes in the form of H⁺ ions and vice versa, negative ions (-Ve) with a similar charge are also present in the acid of aqueous solutions. Therefore, aqueous solutions of acids are good conductors of electricity.

30. Which of the following acids is used in the purification of gold and silver? [S.S.C. Online Graduate Level (T-I) 18.08.2021 (Shift-III) ]

Correct Answer: (a) Nitric acid
Solution:Nitric acid (HNO₃) is commonly used in the purification of gold and silver.

Silver: Silver reacts readily with nitric acid (3Ag + 4HNO₃ → 3AgNO₃ + 2H₂O + NO), forming soluble silver nitrate.

Gold: Gold is unreactive with single acids like nitric acid. However, it can be dissolved by aqua regia, which is a mixture of concentrated nitric acid and hydrochloric acid (in a 1:3 ratio). The nitric acid oxidizes the gold, and the hydrochloric acid provides chloride ions to form tetrachloroaurate(III) ions, which stabilize the gold in solution. After dissolution, gold can be selectively precipitated and purified.

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