`underset((I))underset("But-3-enoic acid")underset()(CH_(2)=CH-CH_(2))-overset(O)overset(||)C-OH " " underset((II))underset("But-3-yonic acid")underset()(CHequivC-CH_(2)-overset(O)overset(||)C-OH)`
In acid (II), the triple bonded carbon atoms are sp hybridised and more electronegative (more electron withdrawing) than the double bonded carbon atoms in acid (I) which are `sp^(2)`hybridised. Therefore, the release of `H^(+)` ion from acid (II) is easier and it is a stronger acid than acid (I).
