Why hard water is unsuitable for laundry purpose?

Water available in a village contains a lot of dissolved CaCl_2 . Which of the following detergents is not suitable for washing purpose ?

Assertion : Calgon is used in the manufacture of soft water used for laundry purpose Reason : Ca^(2+) and Mg^(2+) ions present in hardwater are rendered ineffective by calgon forming their soluble complexes. (I) If both assertion and reason are correct and reason is the correct explanation of assertion. (II) Both assertion and reason are correct but reason is not the correct explanation of assertion (III) If assertion is correct and reason is not correct (IV) Assertion is wrong and reason is correct

Hard water contains ions of

Is demineralised or distilled water useful for drinking purposes? If not, how can it be made useful?

Why hard water is not used in industrial boilers for producing steam?

The hardness of water is estimated by