Question

The presence of following ions have a large effect on the color of glass.

• A. \(Na^+\) ions
• B. \(Ca^{2+}\) ions
• C. \(Fe^{2+}\) ions
• D. \(K^+\) ions

Hint:

Transition metal ions like \(Fe^{2+}\), \(Fe^{3+}\), \(Co^{2+}\), and \(Cr^{3+}\) strongly affect glass color.

Answer 1

The Correct Option is C

The color of glass is strongly affected by transition metal ions. Transition metal ions have partially filled \(d\)-orbitals. Because of electronic transitions between energy levels, these ions can absorb certain wavelengths of light. The remaining transmitted or reflected light gives color to the glass. Iron ions are very important color-producing impurities in glass. Ferrous ion: \[ Fe^{2+} \] can produce greenish or bluish-green shades in glass. Ferric ion: \[ Fe^{3+} \] can produce yellowish or brownish shades. On the other hand, sodium, calcium, and potassium ions are common glass constituents or modifiers. They mainly affect melting behavior, viscosity, and chemical properties. They do not have such a large coloring effect as iron ions. Therefore, the ion having a large effect on the color of glass is: \[ Fe^{2+}. \]