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What chemical could you dissolve in water to make a zinc coating stick to the iron?

I really need your help I'm doing my chemistry homework and the question is: What chemical could you dissolve in water to make zinc coating stick to the iron and explain why? The options are iron sulphate, copper chloride, zinc sulphate [on eBay or Amazon] and magnesium nitrate. Please help I could do with the advice.

Charlotte G.
student - Rotherham, South Yorkshire, England
2007

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We normally won't do students homework for them, Charlotte, but this question struck me as poorly worded, such that you deserve some clarification. Apparently they are asking you to think about the fact that if you want to put a zinc coating on an item you need a source of zinc! So the answer is obviously zinc sulphate.

However, simply dipping iron into zinc sulphate will not cause zinc to deposit as a coating; you'd need to apply electricity to reduce the dissolved zinc to metallic zinc. i.e., to electroplate it onto the iron.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007