A. Stable form of silica upto 870°C
B. Converted to Tridymite on firing between 870 to 1470°C
C. Transformed to Cristobalite on heating above 1470°C
D. All A., B. and C.
Related Mcqs:
- The unit of specific heat at constant pressure, Cp, in SI unit is__________________?
A. W/m2°C
B. J/kg°K
C. W/m°K
D. J/m3°K - The number of H+ in 1 c.c solution of pH 13 is__________________?
A. 6.023 × 1013
B. 6.023 × 1010
C. 6.023 × 107
D. 1013 - Assume that benzene is insoluble in water. The normal boiling points of benzene and water are 80.1 and 100°C respectively. At a pressure of 1 atm, the boiling point of a mixture of benzene and water is__________________?
A. 80.1°C
B. Less than 80.1°C
C. 100°C
D. Greater than 80.1°C but less than 100°C - In case of a solution (not of a solid in a liquid), whose total volume is less than the sum of the volumes of its components in their pure states, solubility is__________________?
A. Independent of temperature
B. Increases with rise in pressure
C. Increased with decrease in pressure
D. Unchanged with pressure changes - pH value of H2SO4 (5% concentration) is__________________?
A. 5
B. 7
C. > 7
D. < 7 - The vapor pressure of water at 100°C is__________________?
A. 100 N/m2
B. 76 cms of Hg
C. 13.6 cms of Hg
D. 760 mm wc - A rigid vessel containing three moles of nitrogen gas at 30°C is heated to 250°C. Assume the average capacities of nitrogen to be Cp = 29.1 J/mole.°C and, Cv = 20.8 J/mole.°C. The heat required, neglecting the heat capacity of the vessel, is__________________?
A. 13728 J
B. 19206 J
C. 4576 J
D. 12712 J - A car tyre of volume 0.057 m3 is inflated to 300 kPa at 300 K. After the car is driven for 10 hours, the pressure in the tyre increases to 330 kPa. Assume air is an ideal gas and Cv for air is 21 J/mole.K. The change in the internal energy of air in the tyre in J/mole is__________________?
A. 380
B. 630
C. 760
D. 880 - In a mixture of benzene vapor and nitrogen gas at a total pressure of 900 mm Hg, if the absolute humidity of benzene is 0.2 kg benzene/kg nitrogen, the partial pressure of benzene in mm Hg is__________________?
A. 180
B. 60.3
C. 720
D. 200 - A gaseous mixture contains 14 kg of N2, 16 kg of O2 and 17 kg of NH3. The mole fraction of oxygen is__________________?
A. 0.16
B. 0.33
C. 0.66
D. 0.47
