Polyphosphates like sodium hexametaphosphate (calgon) are used as water softening agents because they

Question

Polyphosphates like sodium hexametaphosphate (calgon) are used as water softening agents because they (A) form soluble complexes with anionic species (B) precipitate anionic species (C) form soluble complexes with cationic species (D) precipitate cationic species

Tardigrade Admin · Accepted Answer

Polyphosphates like sodium hexametaphos phate (calgon) form soluble complexes with cations like

C a^{2 +}

and

M g^{2 +}

present in hard water and hence used as water softening agents.

N a_{6} P_{6} O_{18} \to 2 N a^{+} + N a_{4} P_{6} O_{18}^{2 -}

M^{2 +} + N a_{4} P_{6} O_{18}^{2 -} \to [N a_{2} M P_{6} O_{_{18}}]^{2 -} + 2 N a^{+}

Q. Polyphosphates like sodium hexametaphosphate (calgon) are used as water softening agents because they

form soluble complexes with anionic species

precipitate anionic species

form soluble complexes with cationic species

precipitate cationic species

Polyphosphates like sodium hexametaphos phate (calgon) form soluble complexes with cations like Ca2+ and Mg2+ present in hard water and hence used as water softening agents. Na6​P6​O18​→2Na++Na4​P6​O182−​ M2++Na4​P6​O182−​→[Na2​MP6​O18​​]2−+2Na+