[Solution from source] In dry HCl, acetone adds one ethanol to give a hemiketal, which with excess ethanol loses water and adds a second ethanol to give the ketal 2,2-diethoxypropane, (CH₃)₂C(OC₂H₅)₂. The hemiketal (CH₃)₂C(OH)(OC₂H₅) is only the intermediate, and no C–C bond forming product like a higher ketone is formed. Answer (1).