⚗️ 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

Which of the following dust collection equipments is the least efficient (for sub-micronic particles) ?Answer: Dust catcher (gravity type) Bag filter design is predominantly dependent on gas temperature, as it affects the gas density & viscosity and the selection of filtering material. The pressure drop in a bag filter isAnswer: Both (b) and (c). Dust collection efficiency of a cyclone separator depends upon itsAnswer: All (a), (b) and (c). Ionisation potential employed in the industrial electrostatic precipitator is of the order ofAnswer: 30 to 70 kV DC The widest explosive limit is of __________ , thereby making it the most explosive gas.Answer: acetylene Aerobic biological oxidation ponds used for the purification of polluted waterAnswer: All (a), (b) & (c). Polluted water having low BOD are most economically treated inAnswer: Oxidation ponds Tri-sodium phosphate is used in boiler water treatment to reduceAnswer: Caustic embrittlement The commonest form of iron & manganese found in ground water as pollutant is in the form of theirAnswer: Bi-carbonates 80% less than 200 mesh size particles are calledAnswer: Powder Coal washing waste water containing about 3% suspended solids (comprising of clay, slate, stone etc.) is treated for solid particles removalAnswer: In sedimentation tanks equipped with mechanical scrapper. Inhalation of lead compounds present in the automobile exhausts (using leaded petrol) causesAnswer: All (a), (b) and (c). TLV of ozone (O₃) and phosgene (COCl₂) in air is __________ ppm.Answer: 0.1 Most of the atmospheric air pollutants are present in large quantity inAnswer: Trophosphere Pick out the wrong statement.Answer: Cooling and freezing of water kills the bacteria present in it. 'Pneumoconiosis' is a disease caused by the inhalation of __________ dust.Answer: Coal The ratio of oxygen available to the oxygen required for stabilisation of sewage is called theAnswer: Relative stability. Pick out the wrong statement.Answer: The radio waves used in the long distance radio communication are reflected back to earth by stratosphere. Most efficient and suitable dust removal equipment for removal of flyash from flue gas in a thermal power plant is theAnswer: Electrostatic precipitator Which of the following is not a secondary air pollutant ?Answer: Sulphur dioxide The concentration of water vapour in troposphere, which depends upon the altitude & temperature varies in the range of zero to __________ percent.Answer: 4 The main industrial source of emission of hydrogen sulphide air pollutant isAnswer: Coal based thermal power plants. Waste/polluted water discharged from electroplating, blast furnace and coal mining industries contain mainly __________ substances.Answer: Inorganic Sound produced by an automobile horn heard at a distance of 1.5 metres corresponds to about __________ decibels.Answer: 120 Most atmospheric air at high temperature (e.g., in summer) having high concentration of Sulphur dioxide causesAnswer: All (a), (b) and (c). Nitrogen oxides (NOx) is not produced in the __________ industry.Answer: Detergent World's worst radioactive pollution was caused by nuclear reactor disaster which occured inAnswer: Chernobyl (undivided U.S.S.R.) Dissolved oxygen content in river water is around __________ ppm.Answer: 5 Oil and grease present in an emulsified state in waste water discharged from industries can be removed byAnswer: Settling out using chemical reagents. The amount of chemical coagulant added for treatment of polluted water __________ with increase in temperature of the polluted water to be treated.Answer: Decreases.