If a solid line represents a covalent bond and a dotted line represents intermolecular attraction, which of these choices shows a hydrogen bond?
-O...H-C-
-N...H-O-
-C...H-F-
H-H

Question

If a solid line represents a covalent bond and a dotted line represents intermolecular attraction, which of these choices shows a hydrogen bond? 
-O...H-C- 
-N...H-O- 
-C...H-F- 
H-H

aaronq · Answer

hydrogen bonds only occur when N,O, or F are bound to H (donating) and N,O,or F are the atom receiving the H.

e.g.  N-H ...O  or   N-H...N

anonymous · Answer

i think the answer is 1 and 2 but i am not sure about it

aaronq · Answer

carbon can't participate in hydrogen bonding because it doesn't have a high enough electronegativity.

anonymous · Answer

what of the third option with hydrogen and florine

aaronq · Answer

carbon doesn't participate in hydrogen bonding