[jjkwest1]

How many of the following molecules have all of their atoms in the same plane?
H2C=CH2 F2O H2CO NH3 CO2 BeCl2 H2O2

a.3
b.4
c.5
d.6
e.7

The answer says c.5  but i got 6 molecules that are all in the same plane. H2C=CH2(trigonal planar), F2) (bent), H2CO(trigonal planar), CO2(linear), BeCl2(linear) and H2O2(trigonal planar). Is the answer suppose to be d.6 instead of c.5 or am i missing something? Thanks

[LQ43]

The answer c. 5 is correct.  (If you have a model kit, build the molecule) http://en.wikipedia.org/wiki/Hydrogen_peroxide

[AWK]

H2O2 shows two planar conformations. Other conformations are nonplanar. Wikipedia shows a real conformation from a crystal but not a minimum energy conformation.