Metals, Minerals, Ores : Properties, Uses Part-2

11. Which one of the following statements is correct? [I.A.S. (Pre) 2003]

(a) Liquid sodium is employed as a coolant in nuclear reactors
(b) Calcium carbonate is an ingredient of toothpaste
(c) Bordeaux mixture consists of sodium sulphate and lime
(d) Zinc amalgams are used as a dental filling

Correct Answer: (b) Calcium carbonate is an ingredient of toothpaste

Solution:

The precipitated calcium carbonates (PCCs) and ground calcium carbonates (GCCs) are used for general-purpose toothpaste, especially dentifrices and other oral care products. Calcium carbonate is insoluble in water, so it can only be used in opaque products, not in clear gels.

12. Match List-I (Industrial process) with List-II (Industry with which associated) and select the correct answer using the codes given below the lists: [I.A.S. (Pre) 2000]

List-I (Industrial Process)	List-II (Industry with which Associated)
A. Cracking	1. Rubber
B. Smelting	2. Petroleum
C. Hydrogenation	3. Copper
D. Vulcanization	4. Edible Fats

Code

	A	B	C	D
(a)	3	2	1	4
(b)	2	3	4	1
(c)	2	3	1	4
(d)	3	2	4	1

Correct Answer: (b)

Solution:

Cracking - Petroleum
Smelting - Copper
Hydrogenation - Edible Fats
Vulcanization - Rubber

13. Match List-I with List-II and select the correct answer using the codes given below the lists: [I.A.S. (Pre) 1999, U.P.P.C.S. (Pre) 2010, U.P.D.U.A./L.D.A. (Pre) 2010]

List-I (Naturally occurring substance)	List-II (Elements Present)
A. Diamond	1. Calcium
B. Marble	2. Silicon
C. Sand	3. Aluminium
D. Ruby	4. Carbon

Code	A	B	C	D
(a)	3	1	2	4
(b)	4	2	1	3
(c)	2	1	3	4
(d)	4	1	2	3

Correct Answer: (d)

Solution:Diamond is a metastable allotrope of carbon where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice.
Marble is a metamorphic rock composed mainly of crystalline calcium carbonate or calcium magnesium carbonate. The most common component of sand is silicon dioxide in the form of quartz.
Ruby is considered one of the four precious stones together with sapphire, emerald, and diamond. The main components of ruby are aluminium, oxygen, and chromium.

14. Which one of the following pairs is not correctly matched? [U.P. R.O./A.R.O. (Pre) 2017]

(a) Aluminium - Bauxite
(b) Copper - Cinnabar
(c) Zinc - Calamine
(d) Iron - Haematite

Correct Answer: (b) Copper - Cinnabar

Solution:The correctly matched lists are as follows:

Aluminium - Bauxite
Copper - Cuprite
Mercury - Cinnabar
Zinc - Calamine (Smithsonite & Hemimorphite)
Iron - Haematite

15. Which of the following is lighter than water? [Uttarakhand U.D.A./L.D.A. (Pre) 2003]

(a) Aluminium
(b) Sodium
(c) Magnesium
(d) Manganese

Correct Answer: (b) Sodium

Solution:Water has a defined density (1 gram per cubic centimeter), while the lightest metals are lighter than water. They are Lithium (0.53 g/cm³), Potassium (0.862 g/cm³), and Sodium (0.971 g/cm³). These are malleable and highly reactive, so they are impractical to use as the basis of an alloy with any structural utility.

16. Which one of the following is the correct sequence of the given substances in the decreasing order of their densities? [I.A.S. (Pre) 2005]

(a) Steel > Mercury > Gold
(b) Gold > Mercury > Steel
(c) Steel > Gold > Mercury
(d) Gold > Steel > Mercury

Correct Answer: (b) Gold > Mercury > Steel

Solution:

Substance	Density (g/cm³)	Density (Kg/m³)
Gold	19.3	19,300
Mercury	13.6	13,534
Steel	7.8	7,870

Thus, from the above table, we see the correct sequence of decreasing order of the substances is Gold > Mercury > Steel.

17. Which of the following has the highest melting point? [66th B.P.S.C. (Pre) (Re. Exam) 2020]

(a) Boron
(b) Silicon
(c) Aluminium
(d) None of the above/More than one of the above

Correct Answer: (a) Boron

Solution:

The melting point of Boron is 2453 K, Iron is 1808 K, Silicon is 1693 K, and Aluminium is 933 K. Hence, among the given options, Boron has the highest melting point.

Metals, Minerals, Ores : Properties, Uses Part-2

11. Which one of the following statements is correct? [I.A.S. (Pre) 2003]

12. Match List-I (Industrial process) with List-II (Industry with which associated) and select the correct answer using the codes given below the lists: [I.A.S. (Pre) 2000]

13. Match List-I with List-II and select the correct answer using the codes given below the lists: [I.A.S. (Pre) 1999, U.P.P.C.S. (Pre) 2010, U.P.D.U.A./L.D.A. (Pre) 2010]

14. Which one of the following pairs is not correctly matched? [U.P. R.O./A.R.O. (Pre) 2017]

15. Which of the following is lighter than water? [Uttarakhand U.D.A./L.D.A. (Pre) 2003]

16. Which one of the following is the correct sequence of the given substances in the decreasing order of their densities? [I.A.S. (Pre) 2005]

17. Which of the following has the highest melting point? [66th B.P.S.C. (Pre) (Re. Exam) 2020]

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