(i) Write a chemical reaction useful to prepare the following: 1. Freon-12 from carbon tetrachloride. 2. Carbon tetrachloride from carbon disulphide. (ii) What are ambident nucleophiles? Explain with an example.

(i) Write a chemical reaction useful to prepare the following: 1. Fre

1.	(i) Write a chemical reaction useful to prepare the following: 1. Freon-12 from carbon tetrachloride. 2. Carbon tetrachloride from carbon disulphide. (ii) What are ambident nucleophiles? Explain with an example.
Answer» Solution :(a) (i) 1. Freon-12 from carbon tetrachloride: Freon-12 is prepared by the action of hydrogen fluoride on carbon tetrachloride in the presence of catalytic amount of antimony PENTACHLORIDE. This REACTION is called ..Swarts reaction." `underset("Carbon tetrachloride")(C Cl_(4)) + 2HF overset(SbCl_(5)rarr underset("Freon-12")(C Cl_(2) F_(2)) + 2HCl` 2. Carbon tetrachloride from carbon disulphide: Carbon disulphide reacts with chlorine gas in the presence of anhydrous `AlCl_(3)` as catalyst to given carbon tetrachloride. `underset("carbon disulphide")(CS_(2)) + 3Cl_(2) underset(AlCl_(3))overset("Anhydrous")rarr underset("Carbon tetrachloride")(C Cl_(4)) + S_(2)Cl_(2)` (II) Nucleophiles which can attack through two different sites are called ambident nucleophiles. For example, cyanide group in a resonance hydrid of two CONTRIBUTING structures and therefore it can act as a nucleophile in two different ways: `""^(ө)C= N HARR : C = N^(ө)` It can attack through carbon to form cyanides and through nitrogen to form isocyanides or carbylamines.