Chemistry (Part-II)

Total Questions: 54

11. What is the net charge on Calcium Fluoride? [S.S.C. Online CHSL (T-I) 23.01.2017]

(a) 1+
(b) 0
(c) 1-
(d) 2-

Correct Answer: (b) 0

Solution:Calcium fluoride (CaF) is an electrovalent compound in which the two anions of Ca₂⁺ and F⁻ combine to form an electronegative compound. Hence the total charge on it is zero (0).

12. What happens when one S and one P orbital is hybridized? [S.S.C. Online CHSL (T-I) 20.01.201]

(a) We get three orbitals in a plane
(b) We get two orbitals at 180 degrees
(c) We get two mutually perpendicular orbitals
(d) We get four orbitals directed teahedrally

Correct Answer: (b) We get two orbitals at 180 degrees

Solution:Hybridization of S and P orbitals results in the formation of two orbitals in which 50% S and 50% is the property of P orbitals and both of them are located at 180° with respect to each other.

13. What is the name given to a pure substance having only one type of atom? [S.S.C. Online MTS (T-I) 20.09.2017]

(a) Elements
(b) Molecule
(c) Composite
(d) Solution

Correct Answer: (a) Elements

Solution:An element is a pure substance that consists only of atoms that all have the same number of protons in their nuclei. This is what defines the type of atom.

14. _______ are homogeneous mixtures of two or more components. [S.S.C. Online Graduate Level (T-I) 5.03.2020]

(a) Solutions
(b) Emulsions
(c) Enzymes
(d) Amalgams

Correct Answer: (a) Solutions

Solution:Solutions are defined as homogeneous mixtures where the solute (the substance being dissolved) is uniformly distributed throughout the solvent (the substance doing the dissolving) at a molecular or ionic level. You can't see the individual components with the naked eye.

15. From the following commonly used materials, the one that is not an alloy is- [S.S.C. Online Graduate Level (T-I) 11.09.2016]

(a) Steel
(b) Brass
(c) Bronze
(d) Copper

Correct Answer: (d) Copper

Solution:
Alloys are mixtures of two or more metals, or a metal with one or more non-metals, that are intimately mixed, usually by melting and solidifying. They are designed to have enhanced properties compared to the pure metals.

Copper is a pure element. While it is often used to make alloys, copper itself in its elemental form is not an alloy.

16. Bronze is an alloy of- [S.S.C. Online Graduate Level (T-I) 11.09.2016]

(a) Copper & Tin
(b) Copper & Zinc
(c) Copper & Iron
(d) Iron & Nickel

Correct Answer: (a) Copper & Tin

Solution:Bronze is traditionally an alloy made primarily of copper, with tin as the main additive.

17. Qatar is the highest per capita emitter of the following gases? [S.S.C. Online CHSL (T-I) 21.01.2017]

(a) carbon dioxide
(b) carbon monoxide
(c) ammonia
(d) hydrogen sulfide

Correct Answer: (a) carbon dioxide

Solution:Qatar has the highest per capita CO₂ emissions rate in the world, exceeding 40 metric tons/capita, which is roughly two and a half times the 'United States' 16 metric tons/capita CO, emissions.

18. Sulphur and Chlorine can have what type of bond? [S.S.C. Online CHSL (T-I) 25.01.2017]

(a) Polar covalent
(b) Polyionic
(c) Non-polarcovalent
(d) Ionic

Correct Answer: (a) Polar covalent

Solution:There is a polar covalent bond between sulfur and chlorine. A polar covalent bond is a chemical bond where electrons have a single pair and are shared unequally between atoms. In a polar covalent bond, electrons are not shared equally, as one atom spends more time with electrons from other atoms. In a polar covalent bond, one atom is more negatively electronegative than the other atom and attracts electrons more. An example of a polar covalent bond is between hydrogen and chlorine atoms and also between hydrogen and oxygen atoms.

19. Covalent Bond is also called- [S.S.C. Online CHSL (T-I) 25.01.2017]

(a) Molecular Bond
(b) Proton Bond
(c) Nucleus Bond
(d) Electron Bond

Correct Answer: (a) Molecular Bond

Solution:
Covalent bonds are formed by the sharing of electrons between atoms. This sharing of electrons allows atoms to achieve a more stable electron configuration, often resembling that of a noble gas. The resulting group of atoms held together by covalent bonds is called a molecule. Therefore, a covalent bond is also referred to as a molecular bond because it is the type of bond that holds atoms together to form molecules.

20. _______ bond holds the atoms together within a water molecule. [S.S.C. Online CHSL (T-I) 30.01.2017]

(a) Nonpolar covalent
(b) Polar covalent
(c) Ionic
(d) Coordinate

Correct Answer: (b) Polar covalent

Solution:

The bond that holds the atoms together within a water molecule (H₂O) is a Polar covalent bond.

Oxygen is significantly more electronegative than hydrogen. This means that oxygen attracts the shared electrons in the O-H bonds much more strongly than hydrogen does.
Due to this unequal sharing of electrons, the oxygen atom in a water molecule carries a partial negative charge ( $δ^{-}$ ), and each hydrogen atom carries a partial positive charge ( $δ^{+}$ ).
This unequal distribution of charge creates a polar bond.
The atoms are sharing electrons (rather than transferring them), which defines it as a covalent bond.

Therefore, the O-H bonds within a water molecule are polar covalent bonds.

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