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प्रश्न
When an alkali metal dissolves in liquid ammonia the solution can acquire different colours. Explain the reasons for this type of colour change.
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उत्तर
When an alkali metal is dissolved in liquid ammonia, it results in the formation of a deep blue coloured solution.
\[\ce{M + (x + y) NH_3 -> M^+(NH_3)_x + e^{-1}(NH_3)_y}\]
The ammoniated electrons absorb energy corresponding to red region of visible light. Therefore, the transmitted light is blue in colour.
At a higher concentration (3 M), clusters of metal ions are formed. This causes the solution to attain a copper-bronze colour and a characteristic metallic lustre.
संबंधित प्रश्न
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What are the common physical features of alkali metals?
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By adding gypsum to cement
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(i) High boiling point.
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(iii) High density.
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(i) BeSO4
(ii) MgSO4
(iii) BaSO4
(iv) SrSO4
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(ii) Beryllium sulphate is readily soluble in water as the greater hydration enthalpy of Be2+ overcomes the lattice enthalpy factor.
(iii) Beryllium exhibits coordination number more than four.
(iv) Beryllium oxide is purely acidic in nature.
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