Question

The formula of calgon is:
A. $N{a_2}[N{a_4}{(P{O_3})_6}]$
B. $N{a_4}[N{a_2}{(P{O_3})_6}]$
C. $N{a_4}[N{a_2}{(P{O_3})_3}]$
D. $N{a_2}[N{a_4}{(P{O_3})_4}]$

Answer 1

Hint: Calgon is a market name. It is a complex compound with six phosphate ions forming a ring surrounded by sodium ions. Its chemical name is sodium hexametaphosphate.

Complete step by step solution:
Calgon is the trade name for a complex compound named sodium hexametaphosphate and its formula is ${(NaP{O_3})_6}$. Generally metaphosphates form ring structure. Here, we are asked for hexametaphosphate then surely, option C and D are out. Its complex form is given by $N{a_2}[N{a_4}{(P{O_3})_6}]$ and thus comparing the choices, we can say that option A is the correct one.

Note: There is trimetaphosphate with three phosphate ions forming a ring. But calgon does not have them. That is why we reduced the correct option to A and B. Reading about popular compounds will help relate and remember such compounds.