Phenol or ethanol as a nucleophile for ether formation?
You are adding excess sodium ethanolate so there is the possibility of deprotonation of phenol: $$\ce{C6H5OH + C2H5O- &lt;=&gt; C6H5O- + C2H5OH}$$

If we look at the $\text{p}K_\text{a}$ of ethanol and phenol we have 16 and 9.95 respectively and so the equilibrium above will strongly favour the right hand side. Therefore, the phenoxide ion will dominate as a nucleophile in the mixture, and the major product will be ethyl phenyl ether.