Question

2. pH indicators should be used to test for rusting

Answer 1

Answer:

Ferroxyl indicator is a solution containing potassium hexacyanoferrate(III) and phenolphthalein. It turns blue in the presence of Fe2+ ions, pink in the presence of hydroxide ions, it can be used to detect metal oxidation. It is often used to detect rusting in various situations

Answer 2

pH indicators such as Ferroxyl indicator is used to test for rusting.

Explanation:

• Ferroxyl indicator is potassium hexacyanoferrate(III) and phenolphthalein solution.
• On the addition of indicator it turns blue,it is due to the presence of  $Fe2+$ ions, which is pink due to  the presence of hydroxide ions,
• This indicator can be used to detect metal oxidation.
• It is  used very often to detect rusting in different conditions.
• As soon as iron starts to rust it begins to lose electrons to form iron ions.
• Ferroxyl indicator will turn blue due to the presence of iron ions.
• A pink colour reoductis also produced by the ferroxyl indicator.
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