Direction of the shift of electron pair
The direction of the shift of electron pair can be decided on the basis of subsequent points.
(i) While the sets related to a multiple bond are similar, the shift can take place in either direction.
(ii) While the dissimilar sets are related on the two ends of the double bond, the shift is decided through the direction of inductive effect.
In the case of carbonyl group, the shift is all time tends to oxygen, that is more electronegative atom.
In cases in which inductive effect and electromeric effect at the same time carry out, generally electrometric effect predominates.