Physical Chemistry> Haloalkanes react with KCN to form alkyl ...

Haloalkanes react with KCN to form alkyl cyanides as main product while AgCN forms isocyanides as the chief product. Explain.

Jayant Kumar , 11 Years ago

Grade 11

9 Answers

Gaurav

Last Activity: 10 Years ago

CN- is an ambient nucleophile i.e. it can form bond from both C and N atoms. KCN is an ionic compound so both C and N sides are available for the formation of bond, but C-C bond is stronger than C-N bond so cynide is formed. AgCN is a covalent compound so only N side is available for CN to form bond and thus isocynide is formed

mahi

Last Activity: 8 Years ago

KCN is predominantly ionic that is it gives ions in solution .since both Cand N are in position to give electrons but C-C bond is more stable then C-N bond so cyanide is formed but in AGCN the bond between AG andC is covalent so nucleophilic attack occurs through nitrogen carrying lone pair of electrons.

Shridha Sharma

Last Activity: 8 Years ago

KCN+C₂H₅Cl gives C₂H₅CN+KCl

AgCN+ C₂H₅Cl gives C₂H₅NC+ AgCl

is 1 reaction suggests being an ambident nucleophile CN can attached with Cor N , When KCN is present K is highly reactive metal and forms ionic means strong bonds as bonds break Kgoes with Cl , C released its positive bond and required another positive part so attached with C of C₂H_5, while in case of formation of C₂H₅NC molecule there was no +ve or -ve charges so C₂H₅⁺ attracts towards lone pairs of N

Amrinder Dhaliwal

Last Activity: 8 Years ago

Cyanite group act as a ambident nucleophile.It can donate the electrone pair from carbon and nitrogen. The nature of KCN is ionic . So Carbon and Nitrogen are both free bond formation but C-C bond stronger then C-N bond. Cyanide is formed .But the case of AgCN nature is covalant . Only Nitrogen is free for bond formation . So AgCN form Isocyanide

zakir

Last Activity: 7 Years ago

CH3-CH2-CL+KCN:->CH3-CH2-CN+CH3-CH2-NA+KCLthis is the rxn. with KCN.the cyanide ion[:−1C≡N:]−The carbon atom is the nucleophile and the reaction isRX alkyl halide +:-C≡N:Δm−−→RCN alkyl cyanide +X-

Saurabh

Last Activity: 7 Years ago

Cyanide ion is an ambident nucleophile alkali metal cyanides like NaCN KCN and periodminently ionic in principal the reactions can occur either through carbon or nitrogen but in practice the reaction occurs through carbon since carbon carbon Bond stronger than carbon nitrogen bond and alkly cyanide are the chief product on the other hand silver cyanide is periodmintally Covenant therefore only nitrogen electron pair is available for Bond formation as a result alkyl isocyanides are the chief products.

kirti garg

Last Activity: 7 Years ago

When haloalkanes react with KCN it gives cynide because KCN bond is ionic bond which can be break down easily and C-C bond formed which is strong .In AgCN covalent bond is form which is difficult to break down and nitrogen gives easily lone pair to carbon and form isocynide.

Shubham

Last Activity: 6 Years ago

1. The Bond btw K and CN is Ionic..i.e weaker than covalent bond.

2. The Bond btw Ag and CN is Covalent/Strong.

so.. in Case of KCN as the bond is weak both C and N are able to donate e- .

Eg. KCN+C2 H5 Cl gives KCL+ C2H5(CN)

WHY CN NOT NC?

AS C-C BOND is stronger than C-N bond..

resulting in formation of Cyanides.

In Case of AgCN ..

Bond is covlent btw ag and cn .. Ag-CN.. . so only N can donate e- .

eg. AgCN+c2h5cl___AgCl+ c2h5(NC).

NC... RESULTING IN FORMATION OF ISOCYANIDE

Yash Chourasiya

Last Activity: 4 Years ago

Dear Student

CN^- is an ambient nucleophile i.e. it can form bond from both C and N atoms. KCN is an ionic compound so both C and N sides are available for the formation of bond, but C-C bond is stronger than C-N bond so cynide is formed. AgCN is a covalent compound so only N side is available for CN to form bond and thus isocynide is formed as the chief product.

I hope this answer will help you.
Thanks & Regards
Yash Chourasiya