When Ethyl alcohol is heated in presence of conc. Sulphuric acid at 413 K, X is formed.  Number of hybrid orbitals of X involved in bonding are

Not only carbon atoms but oxygen atom is also sp3 hybridized. A total of  20 hybrid hybrid orbitals of which 2 sp3  orbitals have one lp each. CH3-CH2-O....-CH2-CH3; sp3     sp3     sp3    sp3    sp3