Q6 of 65 Page 18

What happens when calcium is treated with water?

(i) It does not react with water


(ii) It reacts violently with water


(iii) It reacts less violently with water


(iv) Bubbles of hydrogen gas formed stick to the surface of calcium

When calcium is treated with water, it reacts with water vigorously and to produce a cloudy white precipitate of calcium hydroxide and hydrogen gas is released as bubbles.


Ca(s) + 2 H2O(g) → Ca(OH)2(s) + H2(g)


Sometimes hydrogen bubbles get stuck to the surface of calcium metal making it light and thus calcium starts floating. This reaction is exothermic in nature.

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