Chapter 9, Problem 9.20A

Benzene ( $C_6{H}_6$ ) has two resonance structures, meaning each carbon-car bonbond is equivalent, with a bond strength between a single C—C bond and double $C=C$ .

Estimate the carbon-carbon bond strength in benzene given:
$2C_6{H}_6\left(g\right)+15O_2\left(g\right)\to 12C{O}_2\left(g\right)+6H_{2}O$ $\Delta H°=-633\text{9 kJ}$
Bond dissociation data can be found in Table 9.3. (The strength of the $O=O$ bond in $O_2$ is 498 kJ/mol, and that of a $C=O$ bond in $C{O}_2$ is 804 kJ/mol.)