Question

Calgon is used for water treatment. Which of the following statement is $NOT$ true about Calgon?

• A. Calgon contains the $2^{\text{nd }}$ most abundant element by weight in the Earth's crust.
• B. It is polymeric compound and is water soluble.
• C. It is also known as Graham's salt
• D. It does not remove $C{a}^{2+}$ ion by precipitation.

Answer 1

Answer: (A)

$\to 2^{\text{nd }}$ most abundant element is $"Si"$ and it is not present in calgon $N{a}_6{P}_6{O}_{18}=($ Graham's salt $)$ (Sodium hexametaphosphate)

$\to$ It exist in polymeric form as ${\left(NaP{O}_3\right)}_6$ and water soluble compound

$\to$ It removes $C{a}^{2+}$ in soluble ion but not by precipitation