Ncert Exercises & Solutions

Which of the following statements are correct?

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

b. Copper matte contains ${Cu}_{2} S$ and $ZnS$ .

c. The solidified copper obtained from the reverberatory furnace has a blistered appearance due to the evolution of ${SO}_{2}$ 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)

Correct statements are

(i) A depressant prevents certain type of particle to come to the froth. e.g., NaCN is added as a depessant during separation of PbS and ZnS.

(ii) The Solidified copper obtain from reverberatory furnace has blistered appearance due to evolution of

{SO}_{2}

during the extraction.

(b) and (d) are incorrect statements, and can be correctly stated as

(iii) Copper matte contains

{Cu}_{2} S

and

FeS

(iv) Zinc can be extracted by reduction of

ZnO

with carbon.