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Which of the following statements regarding the borax bead test of transition metal salts is INCORRECT?

Options

  1. ACobalt salts yield a deep blue bead in both oxidizing and reducing flames.
  2. BChromium salts produce a green bead in both oxidizing and reducing flames.
  3. CCopper salts form a blue bead when heated in a reducing flame.
  4. DManganese salts give an amethyst coloured bead in an oxidizing flame and a colourless bead in a reducing flame

Correct answer

C. Copper salts form a blue bead when heated in a reducing flame.

Step-by-step solution

In the borax bead test, different transition metals form characteristic coloured metaborates depending on the nature of the flame. Cobalt forms Co(II) metaborate, which is blue in both oxidizing and reducing flames. Chromium forms Cr(III) metaborate, which is green in both flames. Manganese forms Mn(II) metaborate, which is amethyst (violet) in an oxidizing flame and colourless in a reducing flame. Copper forms Cu(II) metaborate in an oxidizing flame, which is blue when cold (and green when hot). However, in a redu

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