question_answer 64)

  Hardness of water may be temporary or permanent. Permanent hardness is due to the presence of: (a) chlorides of\[~Ca\] and \[Mg\]in water (b) sulphates of \[~Ca\]and \[Mg\] in water (c) hydrogen carbonates of Ca and Mg in water (d) carbonates of alkali metals in water

Answer:

  (a, b, c) Hardness of water is due to presence of following salts:                       \[Ca{{(HC{{O}_{3}})}_{2}};Mg{{(HC{{O}_{3}})}_{2}},CaC{{l}_{2}};MgC{{l}_{2}};\]\[CaS{{O}_{4}};MgS{{O}_{4}};\]