Mass Transfer
Molecular diffusion is caused by the

Activation energy of the molecules
Transfer of molecules from low concentration to high concentration region
Potential energy of the molecules
Thermal energy of the molecules

ANSWER DOWNLOAD EXAMIANS APP

Mass Transfer
An aqueous solution of methanol is to be distilled in a tray column. High pressure steam is available as a source of heat. For a given reflux ratio and overhead composition, two options are being explored; (i) a reboiler is used and (ii) no reboiler is used but steam is fed directly to the bottom of the column. As compared to option (i), in option (ii)

Less number of trays are required
More number of trays are required but the residue composition remains unchanged
Composition of the residue remains unchanged
More number of trays are required and the residue composition is more dilute in methanol

ANSWER DOWNLOAD EXAMIANS APP

Mass Transfer
A distillation column with N plates is being operated under normal conditions. At some point of time, the operation is shifted to total reflux condition (i.e., no product and residue are being withdrawn and feed to the column is stopped). At the new steady state,

The top and bottom compositions correspond to the maximum enrichment available
The top and bottom compositions are unchanged with and without total reflux
Reboiler load and condenser load are minimum
Composition of vapors and that of liquid do not vary throughout the column

ANSWER DOWNLOAD EXAMIANS APP