Tuesday, September 6, 2011

Hardness of Water

1. The hardness of water is due to the presence of 
     (a) Na+ and K+     (b) Na+ and Al3+ 
     (c) K+ and Ca2+    (d) Ca2+ and Mg2+


Ans. (d)


2. Which of the following causes permanent hardness
    (a) NaCl          (b) MgCl2     (c)   KCl     (d)   MgCO3


Ans. (b)


3. Which of the following causes temporary hardness
       (a) NaCl          (b) MgCl2     (c)   KCl     (d)   MgCO3


Ans. (d)


4 Which of the following does not cause permanent hardness
        (a)  NaCl         (b) MgCl2     (c)   CaCl2     (d)   MgSO4


Ans. (a)

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