[aldo.macias]

i understand why all hydrogens are replaced in alpha halogenation under basic conditions but not why only one hydrogen replaced in alpha halogenation under acidic conditions. Can someone enlighten me?

[Babcock_Hall]

It is a Forum Rule (see red link) that you must show us your attempt before we can help you.  What are your thoughts?

[Vidya]

i understand why all hydrogens are replaced in alpha halogenation under basic conditions but not why only one hydrogen replaced in alpha halogenation under acidic conditions. Can someone enlighten me?

I hope you know acidic and basic conditions generate different chemical environments and show their effects in different ways.
We can discuss more once you are very clear about the above point.

[Babcock_Hall]

@OP, Which books or articles have you consulted?