Glass is soluble in

Options

(a) HClO₄
(b) Hf
(c) aqua regia
(d) H₂SO₄

Correct Answer:

Hf

Explanation:

Unlike other halogen acids, HF acid attacks silica and glass. Glass being a mixture of sodium and calcium silicates reacts with HF forming soluble sodium and calcium fluorosilicates respectively. e.g., Na₂SiO₃ + 6HF → Na₂SiF₆ + 3H₂O, CaSiO₃ + 6HF → CaSiF₆ + 3H₂O.