Question

Which is a better lewis acid alcl3or bcl3?

Answer 1

bcl3 is a stronger Lewis acid as the bond formed with the base will involve 2p orbital overlap which is stronger than the 3p orbital overlap in the case of Alcl3.
So BLCL3 is better Lewis than alcl3

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Answer 2

Hey Good morning......

Here is your answer,

The electron accepting ability is more for aluminium chloride is higher so it is acidic.Both  in BCl3 and AlCl3 an empty orbital is present .Since they can accommodate electron pair they are called lewis acid.Since the size of the boron is as small as compared to  size of the aluminium the effectiveness of pulling force of nucleus is more obediently answered by the electron pair present in close vicinity.Because of this BCl3 has more electron gain tendency.Hence BCl3 is strong lewis acid  compared to AlCl3.

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