Which of the following is not true regarding the structure of benzene? a) the carbon-carbon bonds rapidly alternate between single and double bonds. b) the c-c-c bond angles are 120°. c) the hydrogen atoms are equivalent. d) the π bonds are completely conjugated.

a) The carbon-carbon bonds rapidly alternate between single and double bonds.

Explanation:

In benzene we have that the molecule is planar with an sp² hybridization that allow for three π bonds and the carbons atoms are also bonded together via sigma  a sp² hibridization as well as one hydrogen atom. The alternation of or conjugation of the π bond allow the delocalization of these electron along the whole ring.

Therefore, a) is false the carbon-carbon bonds rapidly alternate between single and double bond. The electrons in the π bonds are completely delocalized through the six atoms in the ring.

b) is true since we have a sp² hybridization.

c) and d) are true for the reasons given previously.

In order to answer the question, we convert the measurements given to a common base unit. For this case, we use seconds.

A)   0.02 seconds

B)   0.02 teraseconds x (10^12 s / 1 terasecond) = 2x10^10 seconds

C)   2,500 milliseconds x (1 s / 1000 ms) = 2.5 seconds

D)   25,000 nanoseconds x (1 x 10^-9 s / 1 nanosecond) = 2.5 x 10^-5 seconds

So ,The correct answer is option " D "