Ncert Exercises & Solutions

Which of the following statement is correct?

1.	Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast.
2.	In the extraction of silver, silver is extracted as a cationic complex.
3.	Nickel is purified by zone refining.
4.	Zr, and Ti are purified by the van Arkel method.

1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)

HINT: Nickel is purified by vapour phase refining method.

Explanation:

(a) Cast iron is obtained by remelting pig iron with scarp iron and coke using hot air blast.

(d) Zr and Ti are purified by van Arkel method as:

\underset{Impure}{Zr}

+

2 I_{2} \to

\underset{Volatile}{{ZrI}_{4}} \overset{∆}{\to} \underset{Pure}{Zr} +

2 I_{2}

(b) and (c) can be correctly stated as:

(b)In extraction of silver, silver is extracted as anionic complex [Ag (CN)₂]^-.

(c) In the vapour phase refining, the metal to be refined is converted into its volatile form which is collected and decomposed to give pure metal.

Nickel is purified by vapour phase refining method.

Ni

+

4 CO \to

Ni {(CO)}_{4}

\overset{}{\to}

450 - 470 K

Ni

+

4 CO