Chemical Engineering - Chemical Engineering Basics

21. 

The Al2 O3 content of cryolite in Hall-Heroult's cell is maintained between __________ percent.

A. 2-5
B. 18-20
C. 12-15
D. 6-12

Answer: Option A

Explanation:

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22. 

Number of electrons in the outermost shell of a semi-conductor material is

A. 2
B. 4
C. 6
D. 8

Answer: Option D

Explanation:

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23. 

The velocity at which individual particles from a fluidised bed are carried away by the fluid passing through it, is defined as the

A. minimum fluidisation velocity.
B. terminal velocity.
C. elutriation velocity.
D. superficial velocity.

Answer: Option C

Explanation:

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24. 

Tip of the match stick contains a mixture of

A. K + S
B. K + S + K2Cr2O7
C. S + K2Cr2O7 + White P
D. none of these

Answer: Option C

Explanation:

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25. 

Which of the following is not an ore of aluminium ?

A. Troosite
B. Kaolin
C. Alunite
D. Cryolite

Answer: Option A

Explanation:

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