Why is phenol more reactive than benzene?

Benzene is made from an aromatic ring consisting of 6 carbon atoms and 6 hydrogen atoms, with delocalised electrons in the centre. Phenol has an additional hydroxy (-OH) group on the ring, and the oxygen atom has a lone pair of electrons on it. These electrons are donated into the pool of delocalised electrons, making phenol more electronegative than benzene. This leaves phenol more susceptible to attack by electrophiles than benzene, meaning it is more likely to undergo electrophilic reactions than benzene is.