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 $Ca ^{2+}$ ion by precipitation.

Answer 1

Answer: (A)

$\rightarrow 2^{\text {nd }}$ most abundant element is $"Si" $ and it is not present in calgon $Na _{6} P _{6} O _{18}=($ Graham's salt $)$ (Sodium hexametaphosphate)

$\rightarrow$ It exist in polymeric form as $\left( NaPO _{3}\right)_{6}$ and water soluble compound

$\rightarrow$ It removes $Ca ^{2+}$ in soluble ion but not by precipitation