Question

Consider the following reactions :
‘A’ is:
(A) CH₂ = CH₂ (B) CH₃ – C ≡ CH
(C) CH ≡ CH (D) CH₃ – C ≡ C – CH₃

Answer 1

Answer:

Correct Option is :

(B). CH₃ – C ≡ CH

Explanation:

Refer the attached picture.

For the rest of the options, It is necessary to have a terminal Hydrogen to give precipitate on reaction with Tollen's Reagent (Ag2O).

CH₂ = CH₂ has terminal Hydrogen but hydration(Hg^2+/H^+) of alkenes give alcohols and alcohols can't be reduced by NaBH4.

CH ≡ CH has terminal Hydrogen to react with Ag2O to give ppt but hydration (Hg^2+/H^+) ethynes give Aldehyde which doesn't give 2° alcohol.

CH₃ – C ≡ C – CH₃ It doesn't have Terminal Hydrogen to react with Ag2O to give ppt.

NOTE : For turbidity appearing within 5 minutes, 2° Alcohol must react with Luca's Reagent (ZnCl2/conc.HCl ).