Answer
Left arrow: Going from a lone pair to a bond.
Right arrow: Going from a bond to a lone pair.
Work Step by Step
1. Identify where the tail of the arrow is:
Left arrow: The tail is clearly on a lone pair.
Right arrow: The tail is clearly on a bond.
2. Identify where the head is going to:
Left arrow: It is going to a hydrogen atom. (It is going to form a bond.)
Right arrow: It is going to an oxygen atom. (It is going to form a lone pair.)
** Electrons can't go from a lone pair to another lone pair, therefore, the left arrow has to be forming a bond.
Therefore:
Left arrow: Going from a lone pair to a bond.
Right arrow: Going from a bond to a lone pair.
