Chemistry (Part-V)

11. Which of the following is not an alloy? [S.S.C. Online Constable GD 12.02.2019]

(a) Solder
(b) Silver
(c) Bronze
(d) Brass

Correct Answer: (b) Silver

Solution:Silver is NOT an alloy. Silver (Ag) is a pure element. Solder is an alloy of lead and tin, bronze is an alloy of copper and tin, and brass is an alloy of copper and zinc.

12. After some days, statues of brass and bronze become green due to _______ . [S.S.C. Online Constable GD 14.02.2019]

(a) Corrosion
(b) Oxidation
(c) Decomposition
(d) Erosion

Correct Answer: (a) Corrosion

Solution:Corrosion is the reason why statues of brass and bronze turn green after some days. This green coating is due to the formation of copper carbonate and copper hydroxide as copper in the alloys reacts with carbon dioxide and moisture in the air. This process is a form of corrosion.

13. Constantan is an alloy of Copper and________. [S.S.C. Online Graduate Level (F-I) 9.03.2020]

(a) Nickel
(b) Tie
(c) Aluminium
(d) Iron

Correct Answer: (a) Nickel

Solution:

Nickel is alloyed with copper to make constantan. Constantan is known for its stable electrical resistance over a range of temperatures.

14. An essential component of a mercury mixture is _______ . [S.S.C. Online MTS (T-I) 16.09.2017]

(a) an acid
(b) mercury
(c) a base
(d) a non-metal

Correct Answer: (b) mercury

Solution:Amalgam is a mixture of mercury with another metal, which can be a liquid, soft paste, or solid in any form and these states depend 1 on the amount of mercury in it. In dentistry, amalgams made of mercury with metals like silver, zinc, and tin are used to fill the cavity.

15. Alkali metals can _______ . [S.S.C. Online CHSL (F-I) 7.01.2017]

(a) be highly unstable at room temperature
(b) vaporize at room temperature
(c) easily gain electrons
(d) easily lose electrons

Correct Answer: (d) easily lose electrons

Solution:Easily lose electrons is a characteristic of alkali metals. They have only one electron in their outermost shell, which they readily lose to achieve a stable electron configuration,forming positive ions. This makes them highly reactive.

16. Alkali metals react vigorously with cold water resulting in the displacement of ________ . [S.S.C. Online C.H.S.L. (T-I) 15.04.2021]

(a) Carbon dioxide
(b) Nitrogen
(c) Hydrogen
(d) Oxygm

Correct Answer: (c) Hydrogen

Solution: Hydrogen gas is produced when alkali metals react vigorously with cold water. The general reaction is:
2M(s) + 2H₂O(l) → 2MOH(aq) + H₂(g) (where M is an alkali metal).

17. Metal oxides are _______ in nature. [S.S.C. Online Graduate Level (T-I) 7.06.2019]

(a) Neutral
(b) Organic
(c) Basic
(d) Acidic

Correct Answer: (c) Basic

Solution:Basic is the nature of metal oxides. Metal oxides typically react with acids to form salts and water, which is a characteristic of basic oxides. Some metal oxides can also exhibit amphoteric behavior, reacting with both acids and bases.

18. Which of the following elements is a metalloid? [S.S.C. Online Graduate Level (T-I) 4.06.2019]

(a) Bismuth
(b) Silicon
(c) Tin
(d) Phosphorus

Correct Answer: (b) Silicon

Solution:Silicon is a metalloid among the given elements. Metalloids have properties intermediate between those of metals and non-metals. Bismuth is a metal, tin is a metal, and phosphorus is a non-metal.

19. Which gas is produced in the reaction of dilute acids with metals? [S.S.C. Online MTS (T-I) 5.08.2019]

(a) Nitrogen
(b) Hydrogen
(c) carbon dioxide
(d) oxygen

Correct Answer: (b) Hydrogen

Solution:Hydrogen gas is produced in the reaction of dilute acids with most metals.
The general reaction is: Metal + Acid → Salt + Hydrogen gas.

20. The process of forming a thick oxide layer of aluminum, called: [S.S.C. JE Mechanical Exam 27.10.2020]

(a) Anodizing
(b) Electrolysis
(c) Crystallisation
(d) Electroplating

Correct Answer: (a) Anodizing

Solution:The process of forming a thick oxide layer of aluminium is called ‘anodizing’. For anodization, aluminium is electrolysed with dilute sulfuric acid (H₂SO₄) by making a clean object an anode. The oxygen gas emitted at the anode reacts with aluminium to form a thick layer of oxide. The coating of this oxide can be easily painted to make attractive aluminium objects