Question: At equilibrium the concentration of water in vapour phase (C*) in kg/m3 of air space and the amount of water (m) adsorbed per kg of dry silica gel are related by, C* = 0.0667m. To maintain dry conditions in a room of air space 100m3 containing 2.2 kg of w

• 1. 0.0
• 2. 0.2
• 3. 0.4
• 4. 1.0

Question: Drying operation under vacuum is carried out to __________________?

• 1. Dry those materials which have very high unbound moisture content
• 2. Reduce drying temperature
• 3. Increase drying temperature
• 4. Dry materials having high bound moisture content

Question: Sticky material can be dried in a ________________ dryer ?

• 1. Tray
• 2. Rotary
• 3. Fluidised bed
• 4. None of these

Question: The drying time between fixed moisture contents within the ‘constant rate period’ is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid) ?

• 1. √T
• 2. T
• 3. T1.5
• 4. T3

Question: The minimum number of theoretical plates is required for achieving a given separation in distillation column with_________________?

• 1. No reflux
• 2. Total reflux
• 3. Zero reflux ratio
• 4. Minimum reflux ratio

Question: For which of the following unit operations, Lewis number is of significance ?

• 1. Adsorption
• 2. Binary distillation
• 3. Gas absorption
• 4. Humidification

Question: Heat in BTU necessary to increase the temperature of 1 lb of gas and its accompanying vapour by 1°F is called the________________?

• 1. Latent heat
• 2. Humid heat
• 3. Specific heat
• 4. Sensible heat

Question: With increase in absolute humidity, the dew point of an unsaturated mixture of air and water vapor (at constant pressure and temperature) ?

• 1. Increases
• 2. Remains unchanged
• 3. Decreases
• 4. Decreases linearly

Question: As the reflux ratio decreases, the_________________?

• 1. Separation becomes more efficient
• 2. Number of plates increases
• 3. Column diameter increases
• 4. None of these

Question: Only small amount of evaporation of water produces large cooling effects because of its___________________?

• 1. Large latent heat
• 2. Low viscosity
• 3. Small latent heat
• 4. None of these