Chemistry (Part-XII)

Total Questions: 50

1. Which one of the following is the scientific name of a mineral called Chromite? [S.S.C. Online MTS (T-I) 11.10.2021 (Shift-III) ]

(a) Aluminium chromium oxide
(b) Copper chromium oxide
(c) Silver chromium oxide
(d) Iron chromium oxide

Correct Answer: (d) Iron chromium oxide

Solution:Chromite is a mineral whose chemical composition is primarily iron (Fe) and chromium (Cr) in an oxide (O) form, specifically FeCr₂O₄.

2. Which of the following is a property of silicon dioxide? [S.S.C. Online MTS (T-I) 11.10.2021 (Shift-III) ]

(a) It is a good conductor of electricity.
(b) It is soft.
(c) It has a high melting point.
(d) It is soluble in water.

Correct Answer: (c) It has a high melting point.

Solution:Silicon dioxide (SiO₂), commonly found as quartz, forms a giant covalent network structure. The strong covalent bonds throughout this network require a large amount of energy to break, resulting in a very high melting point (around 1710 °C). It is an insulator (poor conductor of electricity), is hard, and largely insoluble in water.

3. Amino acids are often referred to as the building blocks of _____ . [S.S.C. Online C.H.S.L. (T-I) 19.04.2021 (Shift-II) ]

(a) sugar
(b) carbohydrates
(c) fats
(d) proteins

Correct Answer: (d) proteins

Solution:Amino acids are the fundamental organic molecules that link together via peptide bonds to form long chains, which then fold into complex three-dimensional structures known as proteins.

4. Chemicals called ____ link to form proteins. [S.S.C. Online C.H.S.L. (T-I) 10.08.2021 (Shift-I) ]

(a) citric acids
(b) nitric acids
(c) amino acids
(d) oxalic acids

Correct Answer: (c) amino acids

Solution:Amino acids are the building blocks of a protein molecule. Amino acids are small organic molecules consisting of an alpha (central) carbon atom attached to an amino group, a carboxyl group, and a variable component (or side chain).

5. Phenylmercuric acetate _____ . [S.S.C. Online MTS (T-I) 15.10.2017 (Shift-II)]

(a) Reduces transpiration rate
(b) Increases transpiration rate
(c) Kills the plant
(d) Reduces respiration

Correct Answer: (a) Reduces transpiration rate

Solution:Phenyl mercuric acetate is an organic mercury compound with the chemical formula CH₂COOHgC₆H₅. Earlier this compound was used as a preservative in paints etc. Spraying this compound on the leaves of plants reduces the rate of transpiration in them.

6. Which of the following acids is called the king of acids? [S.S.C. Online MTS (T-I) 15.10.2017 (Shift-II) ]

(a) Carbonic acid
(b) Phosphoric acid
(c) Nitric acid
(d) Sulphuric acid

Correct Answer: (d) Sulphuric acid

Solution:Sulphuric acid (H₂SO₄) is widely referred to as the "king of acids" due to its immense industrial importance, its strong acidic properties, and its extensive use in various manufacturing processes (e.g., fertilizers, chemicals, detergents, dyes).

7. What is the formula of potassium ion in an ideal gas state? [S.S.C. Online CHSL (T-I) 21.01.2017 (Shift-II) ]

(a) K⁺
(b) K²⁺
(c) K²⁻
(d) K⁻

Correct Answer: (a) K⁺

Solution:The atomic number of potassium (K) is 19. Therefore, it has a total of 19 electrons in its orbitals in the normal state. According to the order of filling of its orbitals, the configuration of potassium will be 1s² 2s² 2p⁶ , 3s² 3p⁶ and 4s¹ but the K⁺ ion formed by the loss of 1 electron from the 4s orbital now has 18 electrons and hence the configuration of the K⁺ ion. The inert gas becomes similar to argon (atomic number 18).

8. Which of the following is NOT a noble gas? [S.S.C. Online MTS (T-I) 22.10.2021 (Shift-I) ]

(a) Oxygen
(b) Argon
(c) Krypton
(d) Neon

Correct Answer: (a) Oxygen

Solution:Noble gases are elements in Group 18 of the periodic table, characterized by a full outermost electron shell, making them very unreactive. Argon (Ar), Krypton (Kr), and Neon (Ne) are all noble gases. Oxygen (O) is a reactive nonmetal in Group 16.

9. Which among the following is an example of solid sol? [S.S.C. Online Graduate Level (T-I) 8.08.2017 (Shift-I) ]

(a) Milk of Magnesia
(b) Foam
(c) Coloured gemstones
(d) Rubber

Correct Answer: (c) Coloured gemstones

Solution:A "solid sol" is a type of colloidal system where solid particles are dispersed uniformly throughout a solid medium. Coloured gemstones (like rubies or sapphires) are excellent examples; their vibrant colors often come from trace amounts of impurity ions (solid particles) dispersed within the main solid crystal structure (e.g., chromium in aluminum oxide for ruby).

10. The state in which molecular attractions are very strong is ____ . [S.S.C. Online MTS (T-I) 6.10.2017 (Shift-I) ]

(a) Solid
(b) Liquid
(c) Gas
(d) None of these

Correct Answer: (a) Solid

Solution:Molecular attraction means the force of attraction acting between the molecules is greatest in the solid state of matter. In the solid state, the molecules of matter are arranged in a definite order by staying very close and are bound to each other by a strong force of attraction.

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