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Abdullah Al Mahmud Arafat

How does calcium oxide react with acids?

Bertrand Wengher  Follow

Often, basic oxides can react with acidic oxides:

Al2O3 + Na2O → 2 NaAlO2.

Al2O3 + 3 SO3 → Al2(SO4)3.

As you can see, some oxides can react either as acidic oxide or as basic oxide. These oxides are known as amphoteric.

However, not every pair of oxides reacts in this manner. Al2O3 + CO2 does not give Al2(CO3)3, unless the CO2 pressure is very high (think Le Chatelier’s principle). Instead, Al2(CO3)3 → Al2O3 + 3 CO2 at ordinary atmospheric pressure.

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Anthony A Chiello  Follow

The charge on Calcium is +2.
Since Calcium oxide is a neutral compound so the charge on Oxygen should be -2.
Valency of Oxygen is 2, so a single Oxygen atom can satisfy the need. Therefore formula is CaO.

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Ann Brells  Follow

The reaction of CaO and CH3COOH goes something like what is shown below. I am assuming that there is some water around so the the first reaction occurs…the formation of calcium hydroxide.

CaO + H2O → Ca(OH)2

and then CH3COOH reacts with the Ca(OH)2 to form calcium acetate:

Ca(OH)2 + 2CH3COOH → Ca(CH3COO)2 + 2H2O

Note that if you do this reaction in the presence of NaOH and ‘hot’ CaO you can also get a decarboxylation reaction:

CH3COOH + NaOH + ‘hot’ CaO → CH4 + Na2CO3

So the details of the reaction are important.

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Bill Nugent  Follow

First, CaO will react with water to for Ca(OH)2. From there, it is like any other acid/base reaction. If the Ca2+ ion is solvent with the acid anion, then both will remain in solution while the hydroxide and hydronium ions combine to form water in accordance with their pKa.

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Bill Burniece  Follow

CaO is a basic oxide. Therefore when it reacts with acids, it reacts as a base:

CaO(s) + 2HCl(aq) >>>>>> H2O(l) + CaCl2(aq)

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Andrew Curl  Follow

Well, rapidly….

[math]CaO(s)uparrow + 2HCl(aq) longrightarrow CaCl_{2}(aq) + H_{2}O(aq)[/math]

What about with [math]HNO_{3}(aq)[/math], nitric acid…?

But with sulfuric acid, the metathesis (i.e. partner-exchange) product is the moderately insoluble calcium sulfate… and thus…

[math]CaO(s)uparrow + H_{2}SO_{4}(aq) longrightarrow CaSO_{4}(s)downarrow + H_{2}O(aq)[/math]

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Bradley Bobbs  Follow

Calcium oxide is known as Quicklime. It’s produced by heating calcium carbonate (eg limestone) until the carbon dioxide is driven off leaving calcium oxide. It has a huge affinity for water, producing calcium hydroxide (“slaked lime”) with a highly exothermic reaction. It’s a primary ingredient of Portland Cement, and has been used mixed with sand as a building mortar for thousands of years,

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Askanswerer00zz  Follow

CaO is sparingly soluble in water but is soluble in acid.

However, if you put calcium oxide in an acidic solution, some of it will form salts and water.

For example, CaO + H2SO4 -> CaSO4 + H2O.

Sulphates, phosphates, chlorides, oxalates of calcium are insoluble.

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devingiguere1  Follow
Is it possible to use CaO as a means to remove PFAS from drinking water? It's every where in our water in my county, and obviously my berkey isn't going to help since flouride isn't something that bonds with activated charcoal. ? Feeling frustrated as I have health issues linked to PFAS contamination going all the way back to my infancy.More
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devingiguere1  Follow
What would happen if combined with PFAS? Or plain floride?More
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Ciel Phantomhive  Follow

You should not have used the word “combine” in your question. The correct word is “mix”. In chemistry the word “combine” has a special meaning. We say, for example, “chemically combined together”. Elements combine to form compounds, and can only do so in specific proportions. When mixed, calcium oxide and water react together highly exothermically to form calcium hydroxide:

[math]CaO(s) + H_2O(l)ightarrow Ca(OH)_2(s)[/math] [math]Delta H<<0[/math]

If water is dripped slowly onto a lump of calcium oxide, a hissing is heard as excess water is turned to steam by the heat produced in the reaction.

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Cammie Wait  Follow

CaO is metal oxide of highly electropositive metal calcium and so it forms base on reacting with water/steam.

CaO+H2O=Ca(OH)2.

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