HydrogenhardMCQ SINGLE⭐ Must-Do

The Calgon process removes permanent water hardness efficiently without forming physical precipitateHydrogen Chemistry Question

Question

The Calgon process removes permanent water hardness efficiently without forming physical precipitates. Calgon is chemically Sodium Hexametaphosphate ($Na_6P_6O_{18}$). What is the precise mechanism by which Calgon renders hard water suitable for laundry?

Answer: B

💡 Solution & Explanation

Calgon ($Na_2[Na_4(PO_3)_6]$) softens water by sequestering. It exchanges its internal $Na^+$ ions for the troublesome $Ca^{2+}/Mg^{2+}$ ions to form massive, soluble complex anions like $Na_2[Ca_2(PO_3)_6]$. Since the calcium is trapped in the complex, it cannot precipitate soap as scum.

💬
Still have doubts about this question?
Send it to our AI chemistry tutor on WhatsApp — gets answered in minutes
Ask on WhatsApp →

Practice 22,000+ questions like this

AI-adaptive practice, video lectures, and full IChO (Chemistry Olympiad) content — all in one place.

JEE Advanced · JEE Mains · NEET · IChO · AP Chemistry