Q1: Pick out the wrong statement.

ANS:D - Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum.

The wrong statement is: "A sharp increase in pressure drop gives an indication of the flooding in a distillation column." In a distillation column, a sharp increase in pressure drop typically indicates the onset of weeping rather than flooding. Weeping occurs when liquid accumulates on the tray or packing surface without sufficient vapor flow to sweep it away. This can lead to increased pressure drop as the liquid accumulates and blocks vapor flow, but it does not necessarily indicate flooding, which is the complete failure of vapor-liquid contact due to excessive liquid accumulation. Flooding, on the other hand, occurs when the vapor velocity becomes too high, causing the liquid to be carried up the column without proper separation. This results in poor mass transfer efficiency and reduced separation performance. Flooding is typically indicated by a sudden drop in tray efficiency or by a decrease in vapor-liquid contact area, rather than a sharp increase in pressure drop. Therefore, the correct statement should be: "A sharp increase in pressure drop does not necessarily give an indication of the flooding in a distillation column."