473. The same volume of all gases is representative of their
A. Specific gravities
B. Densities
C. Gas characteristic constants
D. Molecular weights
✅ The correct answer is option D.
475. Superheated vapour behaves like
A. Dry steam
B. Gas approximately
C. An ordinary vapor
D. None of these
✅ The correct answer is option B.
477. Diameter of the rivet to be provided on a 20 mm. thick boiler plate will be __________ mm.
A. 10
B. 20
C. 30
D. 40
✅ The correct answer is option D.
480. Color of brass changes from yellow to __________ after its dezincification which exemplifies selective leaching.
A. Grey
B. Red
C. Orange
D. Violet
✅ The correct answer is option B.
483. Which of the following is prone to cup and cone fracture?
A. Cast iron
B. Soft brass
C. Round specimen of ductile metal
D. Flat tensile specimen of ductile metal
✅ The correct answer is option C.
486. The substance used as a smoke screen in warfare is
A. C₂H₂
B. SiCl₄
C. P₂O₅
D. PCl5
✅ The correct answer is option B.
489. Percentage of argon (by volume) in dry atmospheric air is about
A. 0.09
B. 0.3
C. 0.57
D. 0.94
✅ The correct answer is option D.
492. FeO (s) + CO (g) = Fe (s) + CO₂ (g), k = 0. 435 at 1173E; At equilibrium, what will be the number of moles of CO gas required to reduce one mole of FeO at 1173 K?
A. 1.0
B. 1.3
C. 2.3
D. 3.3
✅ The correct answer is option D.
495. Role of a “collector” in froth floatation is to
A. Form a water repelling film on the mineral surface
B. Create and stabilise the froth
C. Act as a surface
D. Collect the minerals according to their specific gravity
✅ The correct answer is option A.
458. The following thermocouple may be used for measuring temperature upto 1873°K.
A. Chromel-alumel
B. Copper-constantan
C. Platinum-platinum rhodium
D. Iron-constatan
✅ The correct answer is option C.