Which is the most stable crystalline form of silica at room temperature ?

Related Mcqs:

1. Which is the stable form of silica upto 1470°C ?

   A. Quartz B. Cristobalite C. Tridymite D. None of these...

2. Which is the stable form of silica below 870°C ?

   A. Tridymite B. Cristobalite C. Quartz D. None of these...

3. Which is the stable form of silica between 1470°C and the melting point 1713°C ?

   A. Cristobalite B. Tridymite C. Quartz D. None of these...

4. Semi-silica bricks compared to silica bricks have_______________?

   A. Less fusion point B. Better spalling resistance C. Both A. and B. D. Neither A. not B....

5. Which form of silica has the highest specific gravity ?

   A. Quartz B. Cristobalite C. Tridymite D. All have the same specific gravity...

6. Silica bricks are attacked by basic slags at high temperature. Which of the following is not used solely as a binding material ?

   A. Aluminium phosphate B. Water C. Lime D. Plaster of Paris...

7. Refractoriness of a typical silica brick corresponds to Segar cone number, ’32’, which is equivalent to a temperature of _____________ °C?

   A. 1380 B. 1520 C. 1710 D. 1915...

8. Fusion temperature of pure silica (SiO2) is _______________ °C?

   A. 1350 B. 1715 C. 2570 D. 2800...

9. Addition of zircon to silica refractory brick improves its_____________________?

   A. Crushing strength B. Resistance to slag attack C. Both A. and B. D. Neither A. nor B....

10. Silica bricks are never used for lining the____________________?

    A. Beehive coke ovens B. By-product coke ovens C. Dome of blast furnace stoves D. Roof of open hearth furnace...