⚗️ Chemical Engineering Solved MCQs with Answers

Practice 1920 approved ⚗️ Chemical Engineering questions with verified answers from the 🛠️ Engineering Essentials subject for Pakistan exams.

1920 solved MCQs

What is the major constituents of waste/polluted water discharged from textile, pulp & paper, tanning, distillary, dairy and meat packing industries ?Answer: Natural organic products Water filtration rate in a rapid sand filter ranges from __________ kilolitres/m²/hr.Answer: 3 to 6 Hazardous/polluting chemical industries should have an 'exclusion zone' with a green belt and general public access prohibited around it, covering a radius of ____ metres.Answer: 1000 Maximum permissible residual chlorine in treated water should be __________ mg/litre.Answer: 02 to 0.3 Which of the following is the most active zone of atmosphere in which weathering events like rain, storm & lightning occur ?Answer: Troposphere Which is the most widely used coagulant for the treatment of turbid water ?Answer: Alum (aluminium sulphate) Which of the following is not a natural source of air pollution ?Answer: None of these Threshold limit value (TLV) i.e., the maximum permissible safe limit of phosgene gas which Hitler used to use to kill his enemies in 'gas chamber' is about __________ ppm.Answer: <1 Photochemical smog is formed from automobile exhaustAnswer: All (a), (b) and (c). Reinglemann chart is used for the measurement of theAnswer: Smoke density from a chimey. Disinfection of water is done to removeAnswer: Bacteria Which of the following fine dust removal equipments is the most efficient ?Answer: Electrostatic precipitator Which of the following industries discharge mercury as a pollutant ?Answer: Chloro-alkali industry Threshold limit value (TLV) of CO in air is __________ ppm.Answer: 50 Lead exhausted in the atmosphere by automobiles using leaded petrol (i.e. tetraethyl lead for improving octane number) is a lethal air pollutant which causesAnswer: All (a), (b) and (c). Oilish impurities present the effluent discharged from the electroplating industry is normally not removed byAnswer: Chemical coagulation In large thermal power stations very fine particulates present in flue gas are removed byAnswer: Electrostatic precipitators Threshold limit value (TLV) means maximum permissible/acceptable concentration. TLV of phosgene in air is about __________ ppm (parts per million).Answer: 0.2 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 theAnswer: Troposphere Biological oxidation ponds remove organic matters present in the polluted water byAnswer: Both (a) & (b). Which of the following is an adsorbant for removal of nitrogen oxides from gas/air ?Answer: Silica gel Out of the following, TLV of __________ is the minimum (about 0.02 ppm).Answer: MIC (methyl iso-cynate) The average thickness of ozone layer in stratosphere is about __________ dobson unit (DU).Answer: 230 Polyvinyl chloride containers are not suitable for storingAnswer: Foodstuffs Presence of nitrogen in high concentration in contaminated air reduces partial pressure of oxygen in lungs, thereby causing asphyxia (suffocation) leading to death from oxygen deficiency. Concentration of N₂ in contaminated air at which it acts as a natural asphyxant is ≥ __________ percent.Answer: 84 TLV of ammonia, nitrogen dioxide and phenol vapor in air is __________ ppm.Answer: 5 Corrosion in boilers can be prevented byAnswer: All (a), (b) and (c). Water filtration rate in a slow sand filter ranges from __________ litres/m²/hr.Answer: 100 to 200 Lagoons used for purification of polluted waterAnswer: All (a), (b) and (c). The principal gas evolved from sludge digestion tank isAnswer: CH₄