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

Total Questions: 17

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

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. Cracking1. Rubber
B. Smelting2. Petroleum
C. Hydrogenation3. Copper
D. Vulcanization4. Edible Fats

Code

 ABCD
(a)3214
(b)2341
(c)2314
(d)3241
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. Diamond1. Calcium
B. Marble2. Silicon
C. Sand3. Aluminium
D. Ruby4. Carbon

 

CodeABCD
(a)3124
(b)4213
(c)2134
(d)4123

 

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]

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]

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]

Correct Answer: (b) Gold > Mercury > Steel
Solution:
SubstanceDensity (g/cm³)Density (Kg/m³)
Gold19.319,300
Mercury13.613,534
Steel7.87,870

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]

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.