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How would I write the balanced chemical equation for the reaction of aqueous hydrochloric acid with solid magnesium oxide?

The reactants should be HCl(aq) + MgO(s)

I first wrote OH- and 2MgCl as the products and I was wrong.

How would I write it properly and why was my answer wrong?

I had the same problem with aqueous ethanoic acid reacting with solid zinc carbonate for which I wrote:

CH3COOH+(aq) + ZnCO3 --> CO2(g) + H2O(l) + ZnCH3COO

And also, the reaction for aqueous sulfuric acid is neutralised by aqueous magnesium hydroxide.

Correct, answer and reason if I'm wrong please?

Thanks!

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1 Answer

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HCl(aq) + MgO(s) is an acid + base reaction. The products are salt + water.

Hence: 2HCl(aq) + MgO(s) → MgCl2 + H2O

Also, remember that MgCl is not correct, because the chloride ion is Cl-, while the magnesium ion is Mg2+

Firstly, ethanoic acid is: CH3COOH(aq) (not sure if that + was a typo or not)

An acid + base (carbonate) reaction gives the products: salt + water + carbon dioxide.

Hence: 2CH3COOH(aq) + ZnCO3 → (CH3COO)2Zn + H2O + CO2

The (CH3COO)2Zn salt is like that to indicate the O part is connected to the Zn, and there are 2 of them because the zinc ion has a +2 charge, while the ethanoate ion only has a -1 charge!

Lastly: the reaction for aqueous sulfuric acid is neutralised by aqueous magnesium hydroxide.

This is an acid + base again. Hence, the products are salt + water again.

Reaction: H2SO4 + Mg(OH)2 → MgSO4 + 2H2O

You just need to remember the rules of those general types of acid reactions, and then you will be fine!

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