Draw the hydride transfer mechanistic step of the reaction process. In words: The dianion of Formalin forms a carbon-oxygen double bond (C=O, carbonyl) while simultaneously its carbon hydrogen CH bond breaks - "H" leaves as a hydride ion [H:] that acts as a nucleophile to add (1,2Ad) to the polar C=0 group of p chlorobenzaldehyde. This transfer forms a new CH bond to give the conjugate base of p-chlorobenzyl alcohol. Your mechanism should have a total of three double-headed curved arrows to represent the flow of six electrons