Match each metallurgical process in…

Match each metallurgical process in List-I with its essential chemical step in List-II. List-I: (P) Mond process; (Q) Parkes process; (R) van…

Single correct option

Match each metallurgical process in List-I with its essential chemical step in List-II.

List-I: (P) Mond process; (Q) Parkes process; (R) van Arkel-de Boer process; (S) MacArthur-Forrest cyanide process.

List-II: (1) Silver is extracted from molten lead into zinc, in which it is more soluble, and the zinc is later removed by distillation; (2) Impure nickel reacts with

\mathrm{CO}

at about

330

350\ \mathrm{K}

to give a volatile carbonyl that decomposes at about

450

470\ \mathrm{K}

; (3) Impure zirconium or titanium is converted by

\mathrm{I_2}

into a volatile iodide that decomposes on a hot tungsten filament; (4) Finely ground gold ore is leached with dilute

\mathrm{NaCN}

in air to give a soluble dicyanoaurate(I) complex, from which gold is displaced by zinc dust; (5) A copper-rich matte is blown with air to convert

\mathrm{Cu_2S}

to blister copper.

A. P $\to$ 3, Q $\to$ 1, R $\to$ 2, S $\to$ 4
B. P $\to$ 2, Q $\to$ 1, R $\to$ 3, S $\to$ 4
C. P $\to$ 2, Q $\to$ 4, R $\to$ 3, S $\to$ 5
D. P $\to$ 3, Q $\to$ 5, R $\to$ 2, S $\to$ 1

Show answer and solution

Answer: (B) P $\to$ 2, Q $\to$ 1, R $\to$ 3, S $\to$ 4

Check each pair.
P: the Mond process refines nickel by forming volatile

\mathrm{Ni(CO)_4}

near 330-350 K and decomposing it near 450-470 K, which is statement (2).
Q: the Parkes process desilverises lead by shaking molten lead with zinc; silver is much more soluble in zinc, and the zinc-silver crust is later separated by distillation, which is statement (1).
R: the van Arkel-de Boer process makes ultra-pure Zr or Ti by forming a volatile iodide (

\mathrm{ZrI_4}

) with

\mathrm{I_2}

and decomposing it on a hot tungsten filament, statement (3).
S: the MacArthur-Forrest process dissolves gold as

[\mathrm{Au(CN)_2}]^-

in aerated

\mathrm{NaCN}

and then precipitates it with zinc dust, statement (4).
Statement (5) describes the Bessemerisation of copper matte and matches none of the four processes. The only option with all four pairs correct is P

\to

2, Q

\to

1, R

\to

3, S

\to

4. In the other options at least one pair is wrong, for example option 1 interchanges the Mond and van Arkel steps.

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Original question written in the JEE Advanced 2022 Paper 2 pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake