Chemical Engineering - Chemical Engineering Basics

41. 

Electrometallurgical methods of metal extraction is normally used for those metals

A. whose oxide/ore is not reduced by carbon.
B. which fall in the category of alkali & alkaline earth metals.
C. which stands higher in the electrochemical series of the metal.
D. all (a), (b) & (c).

Answer: Option D

Explanation:

No answer description available for this question. Let us discuss.

42. 

Lowering of recrystallisation temperature of metals can be achieved by its

A. grain refinement.
B. purification.
C. working at lower temperature.
D. all a, b & c.

Answer: Option D

Explanation:

No answer description available for this question. Let us discuss.

43. 

An example of a buffer solution is

A. mercury
B. lime water
C. human blood
D. concentrated nitric acid

Answer: Option C

Explanation:

No answer description available for this question. Let us discuss.

44. 

A solid aluminium ball, when quenched in a water bath maintained at 40°C, cools down from 550°C to 450°C in 20 seconds. The expected temperature of the ball after next 20 seconds may be about __________ °C.

A. 370
B. 340
C. 320
D. 300

Answer: Option A

Explanation:

No answer description available for this question. Let us discuss.

45. 

Name the safety device used to protect the boiler, when the water level falls below a minimum level.

A. Blow down valve
B. Blow off cock
C. Fusible plug
D. Safety valve

Answer: Option C

Explanation:

No answer description available for this question. Let us discuss.