Practice Pakistan's most useful MCQs for competitive exams

Which of the following is the most detrimental for water used in high pressure boiler ?

• (A)  Silica
• (B)  Turbidity
• (C)  Phenol
• (D)  Dissolved oxygen

Answer

Submitted By :Ali Uppal

Septic tanks are used for the ______________ of the deposited solids?

• (A)  Separation
• (B)  Anaerobic decomposition
• (C)  Aerobic decomposition
• (D)  None of these

Answer

Submitted By :Ali Uppal

Waste/polluted water discharged from electroplating, blast furnace and coal mining industries contain mainly _____________ substances?

• (A)  Radioactive
• (B)  Organic
• (C)  Inorganic
• (D)  None of these

Answer

Submitted By :Ali Uppal

Particulates (< 1μm size) remaining suspended in air indefinitely and transported by wind currents are called_________________?

• (A)  Fumes
• (B)  Mists
• (C)  Smoke
• (D)  Aerosols

Answer

Submitted By :Ali Uppal

The type of bacteria which is active in trickling filter during biological treatment of sewage is the _____________ bacteria?

• (A)  Anaerobic
• (B)  Saprophytic
• (C)  Aerobic
• (D)  Parasitic

Answer

Submitted By :Ali Uppal

Presence of _____________ hardness is responsible for the temporary hardness in water?

• (A)  Carbonate
• (B)  Calcium
• (C)  Chloride
• (D)  Sulphate

Answer

Submitted By :Ali Uppal

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 is__________________?

• (A)  Inversely proportional to viscosity of gas
• (B)  Proportional to the viscosity & density of the gas
• (C)  Proportional to the pressure of the gas
• (D)  Both

Answer

Submitted By :Ali Uppal

Limestone powder is injected during pulverised coal burning in boilers to ______________ the flue gases?

• (A)  Reduce SO2 content in
• (B)  Catalytically convert SO2 to SO3 in
• (C)  Increase the dew point of
• (D)  None of these

Answer

Submitted By :Ali Uppal

The main industrial source of emission of hydrogen sulphide air pollutant is________________?

• (A)  Petroleum refineries
• (B)  Coal based thermal power plants
• (C)  Pulp and paper plant
• (D)  Metallurgical roasting & smelting plant

Answer

Submitted By :Ali Uppal

Moist atmospheric air at high temperature (e.g., in summer) having high concentration of sulphur dioxide causes________________?

• (A)  Fading of dyes on textiles
• (B)  Corrosion, tarnishing & soiling of metals
• (C)  Reduced strength of textiles
• (D)  All

Answer

Submitted By :Ali Uppal