A sample of well water contains 140 gm/m3 Ca2+ ions and 345 gm/m3 Na+ ions. The hardness of the sample of water, expressed in terms of equivalent CaCO3 in gm/m3 is (assuming atomic masses of Ca :40, Na : 23, C : 12, O : 16) ?

Related Mcqs:

1. Equal masses of CH4 and H2 are mixed in an empty container. The partial pressure of hydrogen in this container expressed as the fraction of total pressure is___________________?

   A. 1/9
   B. 8/9
   C. 1/2
   D. 5/9

2. A vessel of volume 1000 m3 contains air which is saturated with water vapour. The total pressure and temperature are 100 kPa and 20°C respectively. Assuming that the vapour pressure of water at 20°C is 2.34 kPa, the amount of water vapour (in kg) in the vessel is approximately ?

   A. 17
   B. 20
   C. 25
   D. 34

3. N2 content in a urea sample was found to be only 42%. What is the actual urea content of the sample? (Molecular weight of urea = 60) ?

   A. 80%
   B. 90%
   C. 95%
   D. 98%

4. What is the simplest formula of a compound containing 50% of element A (atomic weight = 10) and 50% of element B (atomic weight = 20) ?

   A. AB3
   B. A2B3
   C. A2B
   D. AB2

5. In _______________ process, ions of salts react with water to produce acidity or alkalinity ?

   A. Hydration
   B. Hydrolysis
   C. Electrolysis
   D. Dialysis

6. Concentration of a solution expressed in terms of _______________ is independent of temperature?

   A. Molarity
   B. Normality
   C. Molality
   D. None of these

7. Atoms of the same element, but of different masses are called__________________?

   A. Isobars
   B. Isotones
   C. Isotopes
   D. None of these

8. pH value of a solution containing equal concentration of hydroxyl and hydrogen ions will be_________________?

   A. 0
   B. 10
   C. 7
   D. 14

9. In the reaction, Ca + 2H2O = Ca(OH)2 + H2; what volume (c.c.) of hydrogen at STP would be liberated, when 8 gm of calcium reacts with excess water ? (Atomic weight of calcium = 40) ?

   A. 4480
   B. 2240
   C. 1120
   D. 0.4

10. The vapor pressures of benzene and toluene are 3 and 4/3 atmospheres respectively. A liquid feed of 0.4 moles of benzene and 0.6 moles of toluene is vaporised. Assuming that the products are in equilibrium, the vapor phase mole fraction of benzene is_________________?

    A. 0.4
    B. 0.6
    C. 0.8
    D. 0.2