Carborundum used for making crucibles for melting non-ferrous metals is chemically________________?

Related Mcqs:

1. Beryllia (which is used in making crucibles for melting uranium & thorium) is superior to alumina in all respects for high temperature (> 1900°C ) use, except______________?

   A. Cost
   B. Electrical conductivity
   C. Thermal conductivity
   D. Fusion point

2. The vapor pressure of a substance, at its melting point, is _____________ in the solid state as compared to that in the liquid state?

   A. Less
   B. More
   C. Same
   D. Either A. or B.; depends on the nature of the substance

3. During a phase change process like sublimation, vaporisation, melting etc., the specific ____________ does not change?

   A. Enthalpy
   B. Gibbs free energy
   C. Internal energy
   D. Entropy

4. Boiling point of a non-homogeneous mixture of immiscible liquids is _____________ that of any one of its separate components?

   A. Lower than
   B. Higher than
   C. Equal to
   D. Either A. or B.; depends on the liquids

5. The vapor pressure of the solvent decreased by 10 mm Hg, when a non-volatile solute was added to the solvent. The mole fraction of the solute in the solution is 0.2. What should be the mole fraction of the solvent, if the decrease in vapor pressure of the solvent is required to be 20 mm Hg ?

   A. 0.2
   B. 0.1
   C. 0.4
   D. 0.6

6. Osmotic pressure of a dilute solution of a non volatile solute in a solvent obeying Raoult’s law is proportional to the_____________?

   A. Temperature
   B. Volume of solution
   C. Moles of non-volatile solute
   D. None of these

7. Addition of a non-volatile solute to a solvent produces a ______________ in its solvent?

   A. Freezing point elevation
   B. Boiling point depression
   C. Vapor pressure lowering
   D. All A., B. & C.

8. Which of the following terms of Vander Walls equation of state for a non-ideal gas accounts for intermolecular forces ?

   A. RT
   B. P + (a/V2)
   C. (V – b)
   D. 1/RT

9. Addition of a non-volatile solute to a pure solvent ____________________?

   A. Increases its freezing point
   B. Increases its boiling point
   C. Decreases its freezing point
   D. Both B. and C.

10. Heat of neutralisation of HCl and NaOH is – 57.46 kJ/Kg mole. The heat of ionisation of water will be _____________ kJ/Kg mole?

    A. 57.46
    B. -57.46
    C. 114.92
    D. -28.73