Chemical Engineering - Environmental Engineering

31.
Threshold limit value (TLV) means maximum permissible/acceptable concentration. TLV of phosgene in air is about __________ ppm (parts per million).
0.002
0.2
1.2
4.8
Answer: Option
Explanation:
No answer description is available. Let's discuss.

32.
The density of the gases (present in air) decreases with increasing altitude to such an extent, that about 70% of the mass of atmospheric air is found in the lower 5 km. of the atmosphere. This lower region of atmosphere is called the
ionosphere
troposphere
stratosphere
none of these
Answer: Option
Explanation:
No answer description is available. Let's discuss.

33.
Biological oxidation ponds remove organic matters present in the polluted water by
using the activities of bacteria and other micro organisms.
aerobic oxidation.
both (a) & (b).
neither (a) nor (b).
Answer: Option
Explanation:
No answer description is available. Let's discuss.

34.
Which of the following is an adsorbant for removal of nitrogen oxides from gas/air ?
Active carbon
Silica gel
Bog iron (iron oxide)
Pulverised limestone
Answer: Option
Explanation:
No answer description is available. Let's discuss.

35.
Out of the following, TLV of __________ is the minimum (about 0.02 ppm).
phosgene
bromine
MIC (methyl iso-cynate)
ozone
Answer: Option
Explanation:
No answer description is available. Let's discuss.