question_answer 37)

    What happens when calcium is treated with water? (i) It does not react with water. (ii) It reacts violently with water. (iii) If reacts less violently with water. (iv) Bubbles of hydrogen gas formed stick to the surface of calcium. (a) (i) and (iv)                     (b) (ii) and (iii)                    (c) (i) and (ii)                      (d) (iii) and (iv)

Answer:

                  (d) Calcium reacts less violently with water and the bubbles of hydrogen gas produced stick to the surface of calcium, Due to which it floats over water surface.                 Much less heat is produced in this reaction due to which hydrogen gas formed does not catch fire.