Question

ixD Colors of selected lons Simple Cations in Aqueous Solution in neutral or basic solution) Ni Fe Cu (in acidic solution) Mn (in concentrated solution) Yellow to Orange Fe. Complex lons in Aqueous Solution Cu (NH purple: Croiz Yellow; Cr20, Colorless: Simple Cations During Flame Tests Crimson (purple-red): sr Blue to Green: (persistent) Yellow to Green Ba 2 (fleeting) orange to Red: (short-lived) Purple: K (weak) Flame tests are limited by interferences due to the presence of other ions. Yellow to Orange: Na (intense, persistent)
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Answer 1

Group III cations include Zn^z +, AI^, Ni^2 +, Co^2 +, Mn^2 +, Cr^2 + and Fe^2 + ions. These cations produce slightly soluble sulphides and have the Ksp values more than 10^-20. Hence they require high quantities of basic H_2S solution to precipitate corresponding sulphide salt. The colour of aqurance solutions of group III cations is as follows: Zn^2 + - Zinc has completely filled d-orbitals and hence is colourless. Aj^2 + - Aluminium reacts with water to form AI(OH)_2 complex and is colourless. NI^2 + - green Co^2 + - pink Mn^2 + - pink if concentrated otherwise colourless with pink is h hue Cr^2 + - The colour of Cr^2 + in aqueous solution is green, if chromium is present as chromate then the colour is yellow and for dichromate it is orange. Fe^2 + ions - The colour of Fe^2 + in aqueous solution is yellow to orange while the colour of Fe^2 + in aqueous solution is green.