Ethyl acetate is treated with excess $\mathrm{C}{}_2\mathrm{H}{}_5\mathrm{MgBr}$ and then with $\mathrm{H}{}_3\mathrm{O}{}^{+}$. The alcohol derived from the acyl part of the ester is

An ester consumes two moles of Grignard reagent: the first gives the ketone $\mathrm{CH}{}_3-\mathrm{CO}-\mathrm{C}{}_2\mathrm{H}{}_5$ (butan-2-one) after loss of ethoxide, and the second adds to it. The product is $\mathrm{CH}{}_3-\mathrm{C}(\mathrm{OH})(\mathrm{C}{}_2\mathrm{H}{}_5){}_2$, i.e. 3-methylpentan-3-ol, a tertiary alcohol.