⚗️ 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

There are thirteen metals which are treated as pollutants. Which of the following metals is not a pollutant ?Answer: Aluminium The function of skimming tank in sewage treatment is to remove __________ substances.Answer: Oil & fatty The weakest sound that can be heard by a person in a quiet environment is equivalent to __________ decibel.Answer: 1 Inorganic impurities causing water pollution isAnswer: Salts of metals The main type of sludge gas evolved during sewage treatment in Imhoff tank isAnswer: CH₄ From pollution control point of view, the maximum permissible concentration of sulphur dioxide in atmospheric air is about __________ ppm.Answer: 5 The pH value of oxidised sewage is aboutAnswer: 7.3 Smog isAnswer: A combination of smoke and fog. __________ is the process of killing organism in water.Answer: Disinfection Reingleman chart No. 2 corresponds to __________ percent black smoke.Answer: 40 Which of the following is a manmade source of air pollution ?Answer: Automobile exhaust. Which is the most efficient dust removal equipment for removal of sub-micronic dust particles from blast furnace gas ?Answer: Electrostatic precipitator Insufficient washing of sand grains in a rapid sand filter causesAnswer: Mud balls Which of the following sources is responsible for maximum air pollution ?Answer: Automobiles exhaust. Which of the following is the most efficient for removal of very finely divided suspended solids and colloidal matter from the polluted water stream ?Answer: Chemical coagulation In sewage treatment, its sedimentation is speeded up by commonly addingAnswer: Lime. Noise level in a quiet private business office is about __________ decibels.Answer: 50 'Safe limit' called Threshold Limit Value (TLV) of carbon monoxide in atmospheric air is < 50 ppm. The main source of carbon monoxide pollutant in air is theAnswer: Automobiles exhaust. Inhalation of silica dust by human being causesAnswer: Both(b) & (c) Which of the following air pollutants is not toxic to vegetation i.e., doesn't cause vegetation damage ?Answer: Carbon monoxide A masonry structure built below ground level, where biochemical reaction takes place due to anaerobic bacteria is calledAnswer: Septic tank A considerable part of the harmful ultraviolet radiation of the sum does not reach the earth surface, because of the fact that, there is a layer of __________ high above earth's atmosphere, which absorbs it.Answer: Ozone White smoke coming out of the chimney of a furnace indicates the use ofAnswer: Very high excess air. TLV of NO₂ & NO exposure for the human being is 5 & 25 ppm respectively. Prolonged exposure of human being to NO₂ causesAnswer: Bronchitis Sulphur dioxide present in the industrial chimney exhaust gases causesAnswer: All (a), (b) and (c). A man exposed to excessive noise level in the working environment may suffer fromCAnswer: All (a), (b) and (c). Which of the following is a secondary air pollutant ?Answer: Photochemical smog Presence of __________ bacteria in water causes disease like typhoid.Answer: Pathogenic CFC (chloro fluoro carbon) is very highly reactive in causing depletion of ozone layer in the atmosphere. Each atom of chlorine liberated from CFC is capable of decomposing __________ molecules of ozones.Answer: 10⁵ Green house gases blanket/block the infrared radiation from earth's surface to the atmosphere leading to its progressive warming up. Which of the following gases does not exhibit green house effect ?Answer: SO₃