Free Chemical Process Principles MCQs with Answers
2,710 Chemical Process Principles MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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- A. Tanneries
- B. Chloro-alkali industry
- C. Beverage plant
- D. Phosphoric acid plant
Explanation: Mercury-cell chlor-alkali plants can discharge mercury through process effluent and emissions.
Correct answer: Chloro-alkali industry- A. All A., B. and C.
- B. Biological oxygen demand
- C. Vapor pressure
- D. Dissolved oxygen content
Explanation: As water temperature rises, the solubility of oxygen decreases, so its dissolved oxygen content falls and aquatic organisms are stressed.
Correct answer: Dissolved oxygen content- A. Phenol and cyanide
- B. Chlorine
- C. Alkalis
- D. Suspended solids
Explanation: Cyanide is extremely lethal because it prevents cells from using oxygen, and phenolic compounds can also be highly toxic to aquatic life.
Correct answer: Phenol and cyanide- A. Aerobic
- B. Pathogenic
- C. Anaerobic
- D. Non-pathogenic
Explanation: Pathogenic bacteria are disease-causing microorganisms, and their presence in drinking water indicates faecal or other biological…
Correct answer: Pathogenic- A. 10
- B. 90
- C. 800
- D. 750
Explanation: The older WHO permissible limit commonly quoted for particulate matter in air is 90 μg/m³.
Correct answer: 90- A. 0.002
- B. 0.2
- C. 1.2
- D. 4.8
Explanation: Phosgene is extremely toxic, so its TLV is very low, about 0.2 ppm in the convention used by this question.
Correct answer: 0.2- A. Toluene
- B. Carbon dioxide
- C. Carbon disulphide
- D. Acetaldehyde
Explanation: Carbon dioxide has the highest TLV among these substances, although the commonly quoted occupational limit is about 5,000 ppm, not 500…
Correct answer: Carbon dioxide- A. Grit chamber
- B. Skimming tank
- C. Trickling filter
- D. Detritus tank
Explanation: A detritus tank is designed to remove fine grit and other heavy inorganic solids from sewage.
Correct answer: Detritus tank- A. All A., B. and C.
- B. Enhancing pH of feed water by adding alkali
- C. Feeding sodium sulphite or hydrazine phosphate to the boilers, which combines with oxygen
- D. and prevents corrosion
- E. Deaeration of feed water
Explanation: Boiler corrosion is controlled by removing dissolved oxygen through deaeration, maintaining suitable alkalinity, and adding oxygen…
Correct answer: All A., B. and C.- A. Respiratory & lung disease
- B. All A., B. and C.
- C. Corrosion of building materials
- D. Reduction in plant's productivity owing to acid rain
Explanation: Sulphur dioxide irritates the respiratory system, contributes to acid rain that damages plants, and forms acidic products that corrode…
Correct answer: All A., B. and C.- A. Benzopyrene
- B. Peroxyacetyl nitrate
- C. Carbon monoxide
- D. Sulphur dioxide
Explanation: Carbon monoxide binds strongly with haemoglobin to form carboxyhaemoglobin, preventing blood from carrying oxygen and causing…
Correct answer: Carbon monoxide- A. 1 to 1.5
- B. 4 to 5
- C. 13 to 14
- D. 6.5 to 8
Explanation: Potable water is normally maintained near neutral, with an acceptable pH roughly from 6.5 to 8.0 or 8.5.
Correct answer: 6.5 to 8- A. Nitric acid plant
- B. Petroleum refinery
- C. Thermal power plant
- D. Sulphuric acid plant
Explanation: A nitric acid plant primarily emits nitrogen oxides, not appreciable sulphur dioxide, because sulphur compounds are not its main feed or…
Correct answer: Nitric acid plant254. Biological oxidation ponds remove organic matters present in the polluted water by _______________?
- A. Using the activities of bacteria and other micro organisms
- B. Both A. & B.
- C. Aerobic oxidation
- D. Neither A. nor B.
Explanation: Oxidation ponds rely on microorganisms, especially bacteria and algae, to biologically degrade organic matter; aerobic oxidation is the…
Correct answer: Both A. & B.- A. Hydrocarbon fuel
- B. Large quantity of excess combustion air
- C. Low amount of excess combustion air
- D. Pulverised coal as fuel
Explanation: Black smoke indicates incomplete combustion, usually because insufficient air is supplied to burn the fuel completely.
Correct answer: Low amount of excess combustion air- A. Methemoglobinemia
- B. Gastroenteritis
- C. Asphyxiation
- D. Tooth decay
Explanation: Excess nitrate is reduced to nitrite in the body, where it converts haemoglobin into methemoglobin and reduces oxygen-carrying capacity.
Correct answer: Methemoglobinemia- A. 5
- B. 50
- C. 2000
- D. 5000
Explanation: The commonly specified threshold limit value for carbon monoxide exposure is 50 ppm.
Correct answer: 50- A. 0.05
- B. 1
- C. 6.5
- D. 15
Explanation: The average environmental lapse rate in the troposphere is approximately 6.5°C per kilometre.
Correct answer: 6.5- A. Coagulation
- B. Irradiation of water by ultraviolet light
- C. Cation exchanger
- D. Chlorine
Explanation: Chlorine is the most widely used disinfectant because it is effective, relatively inexpensive, and leaves a residual that protects water…
Correct answer: Chlorine- A. None of these
- B. Biological decay of vegetable matter
- C. Photochemical oxidation of organic matter
- D. Volcanic eruptions and lightening discharges
Explanation: Volcanic activity, lightning, biological decay, and naturally occurring photochemical reactions can all contribute to air pollution.
Correct answer: None of these