Pick out the wrong statement.

If sufficient residence time (around 8 seconds) is not proivided to the downcoming liquid in the downcomer, it may entrain some vapour.

The liquid head in the downcomer should not be greater than one half the plate spacing to avoid flooding.

The dischare end of the downcomer must project far enough into the tray liquid so that no gas bubbles can enter the open end and by pass the bubble caps.

none of these.