1alkyne has acidic H
H3C
H <<<< acidic
CH3C≡CH + (-)NH2 ---->NH3+?
i thought (-)CH2C≡CH
but answer is CH3C≡C(-)
why am i wrong???????
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5 Answers
1Because the H come from the more electron withdrawing C, which in this case, is on the right of the triple bond
1Alkyl groups are electron donating...or, proton withdrawing. In this problem, a proton is being given to NH2, so u want proton donating. CH3 is the alkyl group here, so it will keep in its Hydrogens. So comparatively, its easier to pull H from the C on the right.
1carbon with sp hybridisation is more electronegative since s- character is 50%.
hence hydrogen attached will be more acidic and NH2- will abstract hydrogen from the triple bond carbon....
39So an acid base reaction culminates.
CH3C≡CH + NH2- ---->NH3+ + CH3C≡C-
This alkynyl anion can be used as a nucleophile in preparation of alkynes by nucleophilic substitution reactions. The acid base rn you have given here is the typical reaction of acetylene with sodamide in liquid ammonia.
