Chemistry (Part-X)

Total Questions: 50

21. Who proposed the 'plum pudding' theory of the divisible atom in which negatively charged electrons were scattered in a lump of positive charge like a raisin in plum pudding? [S.S.C. Online CHSL (T-I) 08.06.2022 (Shift-I) ]

(a) Robert Andrews Millikan
(b) Ernest Rutherford
(c) Sir JJ Thomson
(d) Henri Becquerel

Correct Answer: (c) Sir JJ Thomson

Solution:Sir JJ Thomson proposed the 'plum pudding' theory of the divisible atom in which negatively charged electrons were scattered in a lump of positive charge like a raisin in plum pudding. The plum pudding model is one of several historical, scientific atom models. The plum pudding model has electrons sur-rounded by a volume of positive charge, like negatively charged "plums" embedded in a positively charged "pudding".

22. Zeolite is— [S.S.C. Online Graduate Level (T-I) 27.08.2016 (Shift-I) ]

(a) hydrated ferric oxide
(b) hydrated sodium aluminium silicate
(c) sodium hexameta phosphate
(d) sodium tetraborate

Correct Answer: (b) hydrated sodium aluminium silicate

Solution:Zeolite is a porous alumina silicate mineral that forms naturally in rocks formed from volcanic lava. A large amount of various metallic ions Na⁺, K⁺, Ca²⁺ and Mg²⁺ and others are combined from zeolite. Industrially prepared by the interaction of zeolite-sodium aluminate and sodium silicate reagents.

23. The largest source of pollution in the world is— [S.S.C. Online Graduate Level (T-I) 27.08.2016 (Shift-I) ]

(a) Herbicides and insecticides
(b) Automobile exhausts
(c) Sewage and garbage
(d) Industrial effluents

Correct Answer: (c) Sewage and garbage

Solution:Pollution is an undesirable change in the physical, chemical, and biological characteristics of air, land, and water, which affect the life of human beings or other organisms. The biggest source of pollution in the world is Sewage and Garbage, which pollutes water, air, and soil.

24. Which of the following gases if present in the atmosphere can be detected by its odour? [S.S.C. Online CHSL (T-I) 10.01.2017 (Shift-III) ]

(a) Ethane
(b) Sulfur dioxide
(c) Hydrogen
(d) Carbon monoxide

Correct Answer: (b) Sulfur dioxide

Solution:Sulfur dioxide is a chemical compound. Its chemical formula is SO₂. It is recognized in the environment due to its strong smell. It is a strong toxic gas, which is released in many industrial processes and by volcanoes.

25. Acid rain is caused due to pollution of atmosphere by— [S.S.C. Online Graduate Level (T-I) 27.08.2016 (Shift-I) ]

(a) oxides of nitrogen and sulphur
(b) oxides of nitrogen and phosphorous
(c) oxides of carbon and nitrogen
(d) oxides of nitrogen and methane

Correct Answer: (a) oxides of nitrogen and sulphur

Solution:Sulfur dioxide (SO₂) and oxides of nitrogen {NOx where x = 1, 2, 3} are found in the gases produced by fossil fuels used by humans. These gases react with water vapor and oxygen in the atmosphere to produce sulfuric acid and nitric acid. These acidic water vapors can travel miles through the wind to produce acid rain anywhere.

26. Adding which substances gives green colour to glass? [S.S.C. Online CHSL (T-I) 10.01.2017 (Shift-III) ]

(a) Calcium oxide
(b) Iron oxide
(c) Chromium oxide
(d) Manganese oxide

Correct Answer: (c) Chromium oxide

Solution:Chromium oxide (Cr₂O₃) is added to the glass to obtain a green color. The naturally occurring chromium oxide is known as Eskolaite. Chromium is used for making alloys and in electroplating. Salts of cobalt are added to impart a red color to the glass.

27. Barium nitrate is used in signal flares and fireworks that burns in bright ______ colour. [S.S.C. Online MTS (T-I) 27.10.2021 (Shift-I) ]

(a) Yellow
(b) Blue
(c) Green
(d) Orange

Correct Answer: (c) Green

Solution:Barium nitrate is a colorless inorganic compound with the chemical formula Ba(NO₃)₂. It is toxic in nature and soluble in water. It burns with a green flame.

28. Which of the following is used to remove the green colour from glass? [S.S.C. Online Graduate Level (T-I) 6.03.2020 (Shift-III) ]

(a) Sulphur Dioxide
(b) Manganese Dioxide
(c) Silicon Dioxide
(d) Titanium Dioxide

Correct Answer: (b) Manganese Dioxide

Solution:Manganese dioxide (MnO₂) is used to remove the green color from glass. It is a black-colored substance, which reacts with glass and converts into sodium per magnet, clearing the green color of the glass.

29. Which of the following is the formula of barium peroxide. [S.S.C. Online CPO SI (T-I) 09.11.2022 (Shift-I) ]

(a) Ba₂O₂
(b) BaSO₄
(c) BaO
(d) BaO₂

Correct Answer: (d) BaO₂

Solution:Barium Peroxide:

It is a greyish-white granular solid.
Its chemical formula is BaO₂.
It is a non-combustible chemical.
Though it accelerates the rate of combustion of combustible materials.
It is used as a bleaching agent, in making Hydrogen Peroxide, aluminium welding and textile dyeing.

30. Which of the following is responsible for producing green light in fireworks? [S.S.C. Online C.H.S.L. (T-I) 13.04.2021 (Shift-II) ]

(a) Sodium
(b) Barium
(c) Silicon
(d) Potassium

Correct Answer: (b) Barium

Solution:Barium chloride, a salt of barium (Ba), is used for the production of green light in fireworks and firecrackers. Apart from this, sodium nitrate is used to produce yellow color and copper chloride is used to produce the blue color.

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