Process Equipment and Plant Design
Pick out the wrong statement pertaining to a shell and tube heat exchanger.

Disk and doughnut baffle is the most commonly used baffle
The maximum unsupported tube span is generally about 75 times tube diameter, but is reduced to about 60 times for aluminium, copper & alloys of these
The maximum value of baffle spacing is equal to the I.D. of the shell
The minimum value of baffle spacing is 50 mm