Which are the most abundant elements present inside the earth's crust?

1. Al, and Fe 

2. Al, and Cu

3. Fe, and Cu

4. Cu, and Ag

Extraction of gold and silver involves leaching the metal with $C{N}^{-}$ ion. The metal is recovered by ......

From the following, the ores that are concentrated by froth flotation are:

Choose the correct option:
1. a and b
2. b and c
3. c and d
4. a and d

Reactions among the following that occur during calcination are:

Choose the correct option:
1. a and b
2. b and c
3. c and d
4. a and c

Which of the following ores can be reduced by carbon?

a. Haematite           

b. Zincite          

c. Iron pyrites         

d. Sphalerite

Choose the correct option:
1. a and b
2. b and c
3. c and d
4. a and d

Which of the following statements are correct?

a.  A depressant prevents certain types of particles to come to the froth.

b.  Copper matte contains ${\mathrm{Cu}}_2\mathrm{S}$ and $\mathrm{ZnS}$.

c.  The solidified copper obtained from the reverberatory furnace has a blistered appearance due to the evolution of ${\mathrm{SO}}_2$ during the extraction.

d.  Zinc can be extracted by self-reduction.

Choose the correct option
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, c)

Match the items in Column I with the items in Column II and assign the correct code.

Codes

Match the items in Column I with the items in Column II, and assign the correct code.

 Codes

Match the items of Column I with items of Column II and assign the correct code.

 Codes

           A         B          C          D

1.       3          4           2           1

2.       5          4           3           2

3.       2          3           4           5

4.       1          2           3           4

Match the items of Column I with items of Column II and assign the correct code.

 Codes: