Give reasons
Why do ionic compounds have high melting points?
Why calcium starts floating when calcium reacts with water?
Answers
Explanation:
Ionic compounds are held together by electrostatic forces between the oppositely charged ions .As the ionic lattice contains such a large number of ions, a lot of energy is needed to overcome this ionic bonding so ionic compounds have high melting and boiling points.
This is an exothermic reaction, i.e. heat is released. As the reaction proceeds, bubbles of H2 (g) and a white precipitate of Ca(OH)2are formed. The bubbles formed stick to the surface of calcium metal and make it lighter. Therefore, Calcium floats on water.
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1. Ionic compounds have high forces of attraction between the particle. hence, it is difficult to break the bond between the compound so, they have a high melting point.
2. Calcium reacts with hot water and Hydrogen gas is released and that Hydrogen gas stick to the surface of calcium metal. so calcium becomes light and appears to float.