Which of the following compounds is used for water softening?

(i) Ca₃(PO₄)₂

(ii) Na₃PO₄

(iii) Na₆P₆O₁₈

(iv) Na₂HPO₄

H₂S has minimum boiling point.

PbS + 4H₂O_2->PbSO₄ + 4H₂O.

Volume strength of H₂O₂ = Molarity * 11.2

HF molecules are associated with strong intermolecular hydrogen bonding hence its boiling point is the highest

Compound             Melting Point (K)

HF                          190

HCl