Chemistry (Part-III)

11. Which of the following is not a noble gas? [S.S.C. Online MTS (T-I) 9.10.2017]

(a) Helium
(b) Xenon
(c) Argon
(d) Oxygen

Correct Answer: (d) Oxygen

Solution:Noble gases are in Group 18 of the periodic table and are known for their inertness due to their full outer electron shells. Helium (He), Xenon (Xe), and Argon (Ar) are all noble gases. Oxygen is in Group 16 and is not a noble gas.

12. The common name of the elements of group 17th is: [S.S.C. Online MTS (T-I) 10.10.2017]

(a) Metal
(b) Transition element
(c) Halogen
(d) Noble gas

Correct Answer: (c) Halogen

Solution:The elements of the 17th group in the periodic table are collectively known as Halogen. These elements include Fluorine, Chlorine, Bromine, Iodine, and Astatine.

13. In science, fluids are the common name for: [S.S.C. Online MTS (T-I) 5.10.2017]

(a) Gases only
(b) Liquids only
(c) Both gases and liquids
(d) None of these

Correct Answer: (c) Both gases and liquids

Solution:In science, both gases and liquids are called fluids. These are substances that can flow from one place to another. That is, fluids can flow, whereas solids cannot flow.

14. The chemical symbol of molybdenum is _______ . [S.S.C. JE Electrical Exam 22.03.2021]

(a) My
(b) Mb
(c) Md
(d) Mo

Correct Answer: (d) Mo

Solution:The chemical symbol for molybdenum is Mo. Its atomic number is 42. Molybdenum (Mo) is a d-block element of the periodic table.

15. Electrons in the highest energy level of an atom are called: [SS.C. Online CHSL (T-I) 19.01.2017]

(a) Valence protons
(b) Orbital protons
(c) Valence electrons
(d) Orbital electrons

Correct Answer: (c) Valence electrons

Solution:The highest energy level of an atom is also called the external energy level or valence shell. The electrons found in the valence level are called valence electrons. It is by valence electrons that one atom is attached to another atom and forms molecules by forming covalent or electrovalent bonds.

16. The number of atoms present in the molecule of an element is called- [S.S.C. Online MTS (T-I) 20.09.2017 ]

(a) Connectivity
(b) Atomicity
(c) Chemical formula
(d) Molecular formala

Correct Answer: (b) Atomicity

Solution:The number of atoms present in the molecule of an element is called Atomicity. For example, oxygen (O₂) has an atomicity of 2, and ozone (O₃) has an atomicity of 3.

17. Fuse wire is made of an alloy of______. [S.S.C. Online Graduate Level (T-I) 6.09.2016]

(a) Tin and Lead
(b) Tin and Copper
(c) Lead and Copper
(d) Copper and Silver

Correct Answer: (a) Tin and Lead

Solution:In electrical technology or electronics, a fuse is used as a protective component in a circuit to break the circuit when a current exceeds a certain amount. In this way, other valuable components located in the circuit are saved from getting damaged due to excessive current flow. Most often fuses are made from a metal wire or strip, which melts or breaks due to excessive current flow. They are made of that metal, which has a low melting point. An alloy called solder is commonly used to make fuses. Its melting point is 90 to 450 °C. Solder alloys are made from a mixture of Tin and Lead.

18. Solder is an alloy of which two metals? [S.S.C. Online Stenographer 14.09.2017]

(a) zinc and lead
(b) zinc and copper
(c) tin and zinc
(d) tin and lead

Correct Answer: (d) tin and lead

Solution:

Solder is an alloy of tin and lead. Similar to fuse wire, it has a relatively low melting point and is used to join metal surfaces.

19. ______ gives hardness to stainless steel. [S.S.C. Online Graduate Level (T-I) 29.08.2016]

(a) Zinc
(b) Lead
(c) Carbon
(d) Tin

Correct Answer: (c) Carbon

Solution:The hardness comes from the addition of carbon in the manufacturing of stainless steel. The more carbon is added to iron, the harder the steel becomes, with increasing hardness, its brittleness also increases.

20. Which of the following can be used as a catalyst in Hydrogenation reaction? [S.S.C. Online Graduate Level (T-I) 5.03.2020]

(a) Iron
(b) Palladium
(c) Tungsten
(d) Barium

Correct Answer: (b) Palladium

Solution:Palladium metal is used as a catalyst in the hydrogenation reaction. It has the ability to do a selective reduction. That is, it helps in the selective reduction of C-C bonded compounds.