Chemistry (Part-IX)

21. Which of the following is NOT a use of washing soda? [S.S.C. Online C.H.S.L. (T-I) 04.08.2021]

(a) It is used to make drinking water free from germs.
(b) It is used for removing permanent hardness of water.
(c) It can be used as a cleaning agent for domestic purposes.
(d) It is used in glass, soap and paper industries.

Correct Answer: (a) It is used to make drinking water free from germs.

Solution:It is used to make drinking water free from germs. Washing soda (sodium carbonate) is not typically used to disinfect drinking water. That is usually done with chlorine or other sterilizing agents. Its main uses are in softening water, cleaning, and in industries like glass, soap, and paper.

22. Sodium bicarbonate is the chemical name of which of the following? [S.S.C. Online C.P.O.S.L. (T-I) 1.07.2017]

(a) Baking soda
(b) Laundry powder
(c) Plaster
(d) Flying ash

Correct Answer: (a) Baking soda

Solution:Sodium bicarbonate (NaHCO₃) is the chemical name of Baking Soda. Baking powder is formed by mixing baking soda and a weak acid. It is used in increasing the volume of cakes, bread, etc.

23. The common name of dichlorodifluoromethane is ______ . [S.S.C. Online CHSL (T-I) 1.02.2017]

(a) Galena
(b) Freon
(c) Gypsum
(d) Borax

Correct Answer: (b) Freon

Solution:Freon : The common name of dichlorodifluoromethane (

CC l_{₂} F₂

) is Freon. It was widely used as a refrigerant.

24. The Plaster of Paris should be stored in a/an container? [S.S.C. JE Mechanical Exam 27.10.2020]

(a) Water
(b) Kerosene
(c) Moisture-proof
(d) Acid

Correct Answer: (c) Moisture-proof

Solution:The chemical name of Plaster of Paris (POP) is Calcium Sulphate hemihydrate (CaSO₄.½H₂O). Plaster of Paris is kept in a moisture-proof container because it absorbs water in the presence of moisture to form the solid material gypsum, due to which it loses its properties of solidification by mixing with water.

25. The Chemical formula of Ammonium Nitrate is _____ . [S.S.C. Online CHSL (T-I) 2.42.2017]

(a) (NH₂)₂NO₃
(b) NH₄NO₃
(c) NH₄(NO₃)₂
(d) NH₂NO₃

Correct Answer: (b) NH₄NO₃

Solution:Ammonium nitrate is an inorganic compound with the chemical formula NH₄NO₃. In agriculture, ammonium nitrate is used as a high nitrogen fertilizer. It is a white-colored crystalline solid at ordinary temperature and pressure. Ammonium nitrate is used as an oxidizing agent in explosives.

26. What is the molecular formula for hydrochloric acid? [S.S.C. Online C.H.S.L. (T-I) 9.08.2021]

(a) HCl
(b) H₂SO₄
(c) KOH
(d) HNO₃

Correct Answer: (a) HCl

Solution:The acid formed by the combination of hydrogen (H) and chloride (Cl) has the molecular formula of hydrochloric acid (HCI). That is, one atom of hydrogen and one atom of chlorine are combined in one molecule of this acid.

27. The chemical formula of Cadmium Nitrate is ______. [S.S.C. Online CHSL (T-I) 21.01.2017]

(a) Cd(NO₃)₂
(b) CdNO₃
(c) Cd₂(NO₃)₂
(d) Cd₂NO₃

Correct Answer: (a) Cd(NO₃)₂

Solution:The chemical formula of Cadmium Nitrate is Cd(NO₃)₂.

28. Which of the following substances is used in black and white photography? [S.S.C. JE Mechanical Exam 27.10.2020]

(a) Calcium nitrate
(b) Silver bromide
(c) Sodium Chloride
(d) Calcium hydroxide

Correct Answer: (b) Silver bromide

Solution:Silver bromide (AgBr) is used in black-and-white shading. Silver iodide (AgI) is used for artificial rain. Sodium chloride is a compound found in seawater which is a major source of salt. Calcium hydroxide [Ca(OH)₂] is called slaked lime.

29. The chemical formula of acetic acid is _____ . [S.S.C. Online CHSL (T-I) 22.01.2017]

(a) CH₃COH
(b) CH₃COOH
(c) CH₃COCH₃
(d) CH₂COOH

Correct Answer: (b) CH₃COOH

Solution:Acetic acid is an organic acid with the chemical formula CH₃COOH. It is an important chemical reagent and industrial chemical, mainly used in the manufacture of polyethylene terephthalate for soft drink bottles, cellulose acetate for photographic film, polyvinyl acetate for wood glue, and synthetic fibers and fabrics.

30. The chemical formula of urea is _____ . [S.S.C. Online CHSL (T-I) 24.01.2017]

(a) (NH₄)₂CO₂
(b) (NH₂)CO
(c) (NH₄)₂CO
(d) (NH₂)₂CO

Correct Answer: (d) (NH₂)₂CO

Solution:Urea is an organic compound with the chemical formula (NH₂)₂CO. It is a colorless, odorless, white, cheesy, poisonous solid substance. It is found in the urine of mammals and reptiles. Urea is largely produced by the reaction of liquid ammonia and liquid carbon dioxide. The use of urea fulfills the fertilizer power of the soil and the amount of nitrogen required by the plant. It is the first organic compound created in the laboratory.