491. Lime and soda ash are added to water to remove September 7, 2025 by Admin Bicarbonates & sulphates of calcium and magnesium Undersirable taste and odour Bacteria Its corrosiveness ✅ The correct answer is option A.
492. Metallic soap (e.g. aluminium or calcium salts of fatty acids) can be used September 7, 2025 by Admin As a lubricant As a rust preventive In hard water for cleaning of cloth As a foam depressant in distillation column ✅ The correct answer is option A.
493. Trinitro-toluene (TNT) is September 7, 2025 by Admin Used in glycerine manufacture An explosive Used in dye manufacture None of these ✅ The correct answer is option B.
494. In contact process, SO₃ is absorbed in 97% H₂SO₄ and not in water, because September 7, 2025 by Admin SO₃ gas is sparingly soluble in water Water forms an acid mist, which is difficult to absorb The purity of acid is affected Scale formation in the absorber is to be avoided ✅ The correct answer is option B.
495. Teflon is September 7, 2025 by Admin Phenol formaldehyde An inorganic polymer Poly tetrafluoroethylene (P.T.F.E.) A monomer ✅ The correct answer is option C.
496. The yield of tar from high temperature carbonisation of dry coal is about __________ percent. September 7, 2025 by Admin 3 12 22 0.3 ✅ The correct answer is option A.
497. Proximate analysis of coal determines its __________ content. September 7, 2025 by Admin Moisture, ash, sulphur & volatile matter Moisture & volatile matter Moisture, sulphur, nitrogen & fixed carbon None of these ✅ The correct answer is option B.
498. Deaeration of water in its treatment is necessary, as it September 7, 2025 by Admin Minimises its turbidity Helps in controlling its taste and odour Minimises its corrosiveness None of these ✅ The correct answer is option C.
499. Concentration of sulphide ores is done usually by September 7, 2025 by Admin Roasting Smelting Froth floatation Electro magnetic separation ✅ The correct answer is option C.
500. Which of the following is an explosive? September 7, 2025 by Admin Nitroglycerene Trintrotoluene (TNT) Cellulose nitrate All of the above ✅ The correct answer is option D.