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20 g of Ca was burnt in the excess of oxygen and the oxide was dissolved in water to make up a two-litre solution. The normality of alkaline solution is: |
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Answer» The reaction takes place as: Ca + 1/2O2→CaO CaO + H2O→Ca(OH)2 Atomic weight of Ca = 40 molecular weight of CaO = 56 molecular weight of Ca(OH)2 = 74 40 g of Ca produces 74grm of Ca(OH)2 1 g of Ca is equivalent to 74/40 gm of Ca(OH)2 = 1.85gm. So 20 g of Ca = 20×1.85 = 37 Or 37/37 = 1 gm equivalent of Ca(OH)2 (Equivalent weight of Ca(OH)2 is 37) Therefore 1 gm is dissolved in 1 litre Hence in two litre it will be So the normality of alkaline solution is 2.0 N |
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