Chemical Engineering Archives

7261. A 25 cm x 25 cm x 1 cm flat sheet weighing 1.2 kg initially was dried from both sides under constant drying rate conditions. It took 1500 seconds for the weight of the sheet to reduce to 1.05 kg. Another 1m x 1m x 1cm flat sheet of the same material is to be dried from one side only.Under the same constant drying rate conditions, the time required for drying (in seconds) from its initial weight of 19.2 kg to 17.6 kg is

1000

1500

2000

2500

✅ The correct answer is option A.

7262. The critical moisture content in case of drying indicates the __________ rate period.

Beginning of falling

Beginning of constant

End of falling

None of these

✅ The correct answer is option A.

7263. Steam distillation is not recommended to be used, if the

Azeotropic mixture is to be separated and the final product is miscible with water

Liquids decompose, if distilled directly at atmospheric pressure

Material can not be distilled by indirect heating even under low pressure, because of the high boiling temperature

Material to be distilled is thermally unstable or has the tendency to react with other components associated with it, at the boiling temperature

✅ The correct answer is option A.

7264. The slope of the operating line for a single component co-current absorber when plotted in terms of mole ratio units is

∞

#REF!

✅ The correct answer is option C.

7265. Wetted wall tower experiment determines the

Molal diffusivity

Volumetric co-efficient

Mass transfer co-efficient

None of these

✅ The correct answer is option C.

7266. Which of the following psychrometric processes is followed by water vapour laden unsaturated air, when it is passed through solid or liquid adsorbent?

Cooling and dehumidification

Heating and dehumidification at almost constant wet bulb temperature

Dehumidification with dry bulb temperature remaining constant

None of these

✅ The correct answer is option B.

7267. For a distillation column operating at minimum reflux, the

Concentration of liquid and vapour leaving a plate will be same

Reflux ratio will be maximum

Number of plates required will be maximum

None of these

✅ The correct answer is option C.

7268. For contacting a highly soluble gas with a liquid

Bubble the gas through liquid

Spray the liquid on gas stream

Either A or B would suffice

None of these

✅ The correct answer is option A.

7269. At constant pressure, with increase of temperature, the dew point will

Increase

Decrease

Remain unchanged

Increase/decrease ; depends on the temperature

✅ The correct answer is option A.

7270. Components, having widely different boiling point in a binary mixture, can be separated using __________ distillation.

Molecular

Extractive

Steam

Simple

✅ The correct answer is option D.