Using vsepr theory, which of these molecules does not have a trigonal planar shape?
a) ammonia (nh3)
b) formaldehyde (h2co)
c) sulfur trioxide (so3)
d) boron trifluoride (bf3)

Ammonia does not have a trigonal shape.

Explanation:

According to VSEPR theory:

Molecules with 3 sigma bonds and no lone pair possess trigonal planar shape irrespective of the number of pi bonds.

Ammonia has 3 sigma bonds and one lone pair.Hence its shape is pyramidal due to bond pair - lone pair repulsion.Formaldehyde (HCHO) has 3 sigma bonds and 1 pi bond.Hence it has trigonal planar shape.Sulfur trioxide has 3 sigma bonds and 3 pi bonds.Boron triflouride (BF_3) has 3 sigma bonds.

Hence except ammonia all other molecules given possess trigonal planar shape.

That result from subduction of oceanic plates beneath lighter continental plates. most of the earth's volcanoes are located around the pacific ring of fire because that the location of most of the earth's subduction zones.

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