How much ethanol is needed for dehydrogenation to obtain 8.8 g of ethanol? the yield is 75%

Let us write down the solution, compose equations according to the condition of the problem:
С2Н5ОН = Н2О + С2Н4 – dehydration reaction, ethylene was obtained;
C2H4 = H2 + C2H2 – dehydrogenation, acetylene is released;
С2Н2 + Н2О = Н2С = СНОН = СН3 – СНО – hydration, vinyl alcohol is formed, which undergoes isomerization, ethanal is released.
Let us indicate the amount of substances, reaction products in moles:
1 mol – ethyl alcohol;
1 mol is ethylene;
1 mol – acetylene;
1 mol is ethanal.
Let’s make the calculations:
M (C2H4O) = 44 g / mol;
W = m (practical) / m (theoretical) * 100;
m (theoretical) = 8.8 / 0.75 = 11.73 g;
Y (theoretical) = m / M = 11.73 / 44 = 0.27 mol;
Y (C2H4O) = 0.27 mol, which means Y (C2H5OH) = 0.27 mol.
Answer: the amount of ethanol is 0.27 mol.