Nitric acid, or HNO3, is a very corrosive mineral acid. Let us examine in greater detail what will occur if it reacts with Al2O3.
Al2O3 is amphoteric in nature which means it can act as both acid as well as base while HNO3 can be considered a very strong acid and can sometimes even act as a nitrating agent. Al2O3, aluminum oxide has wide range of applications in mining and ceramic communities.
In this article, we will discuss important facts about HNO3 + Al2O3 reaction such as the reaction enthalpy, the heat required, the product formed, the type of reaction, the type of intermolecular forces between their compounds, etc.
What is the product of HNO3 and Al2O3 ?
Aluminum Nitrate (Al(NO3)3) and water (H2O) are yielded as products when nitric acid (HNO3) reacts with aluminum oxide (Al2O3).
Al2O3 + HNO3 → Al(NO3)3 + H2O
How to balance HNO3 + Al2O3
The following steps need to be followed while balancing a chemical equation.
- Given below is an unbalanced chemical reaction of HNO3 and Al2O3,
- Al2O3 + HNO3 → Al(NO3)3 + H2O
- Record the moles of each element on the reactant and product sides.
| Element | Reactant | Product |
|---|---|---|
| Al | 2 | 1 |
| H | 1 | 2 |
| N | 1 | 3 |
| O | 6 | 10 |
- Now, the number of moles present on each side of the reactant and product must be equal in order to balance the chemical equation. In this case, the number of moles in each element is varied.
- Hence, in order to balance the moles of elements in both sides HNO3 present in the reactant side must be multiplied by 6, Al(NO3)3 must be multiplied by 2 and water in the product side must also be multiplied by 3.
- Hence, the balanced chemical equation is :
Al2O3 + 6HNO3 → 2Al(NO3)3 + 3H2O
HNO3 + Al2O3 titration
The titration of HNO3 and Al2O3 is categorized as acid-base titration. HNO3 is a strong acid and Al2O3 is an amphoteric base.
Apparatus:
Burette, conical flask, burette stand, beaker, funnel, pipette.
Indicator Used:
Phenolphthalein is used as an indicator here.
Procedure:
- Wash, rinse and fill the burette with a standardized solution of Al2O3 and fit it in a burette stand.
- Pipette out 10ml of HNO3 in a conical flask and add 2-3 drops of phenolphthalein indicator in it.
- Start adding Al2O3 solution in the conical flask in a dropwise manner with constant swirling.
- Color of the HNO3 + Al2O3 solution in the conical flask will change to light pink on reaching the endpoint.
- Repeat these steps to get concurrent readings.
- The concentration of HNO3 is calculated using the formula S1V1 = S2V2.
HNO3 + Al2O3 net ionic equation
The net ionic equation of HNO3 + Al2O3 is
2O2- = 5NO3– + H+
- To derive this net ionic eq following steps are followed:
- Split the strong electrolytes into ions.
- H+ + NO3– + 2Al3+ + 3O2- = 2Al3+ + 6NO3– + 2H+ + O2-
- Cancel the spectator ions on both sides and write down the net ionic equation.
- 2O2- = 5NO3– + H+
HNO3 + Al2O3 conjugate pairs
The conjugate acid-base pairs are:
HNO3 (Conjugate base) = NO3–
H2O (Conjugate base) = OH–
H2O (Conjugate acid) = H3O+
HNO3 and Al2O3 intermolecular forces
The intermolecular forces exhibited by HNO3 are London – dispersion force and dipole-dipole force.
HNO3 + Al2O3 reaction enthalpy
The reaction enthalpy of HNO3 + Al2O3 is -225.41 KJ/mol. The standard enthalpy of the formation of reactants and products is shown below:
| Element | Reaction Enthalpy (KJ/mol) |
|---|---|
| Al2O3 | -167.5 |
| HNO3 | -206.28 |
| Al(NO3)3 | -306.45 |
| H2O | -292.740 |
- Reaction Enthalpy = Enthalpy of product – Enthalpy of reactant
= (-306.45-292.74) – (-167.5-206.28) KJ/mol
= (-599.19) – (-373.78) KJ/mol = -225.41 KJ/mol.
Is HNO3 + Al2O3 a buffer solution ?
HNO3 + Al2O3 is not a buffer solution as HNO3 is a strong acid, and it does not form a weak acid instead form salt, as a product.
Is HNO3 + Al2O3 a complete reaction ?
HNO3 + Al2O3 is a complete reaction because no more reaction occurs after the products are formed.
Is HNO3 + Al2O3 an exothermic or endothermic reaction ?
HNO3 + Al2O3 is an exothermic reaction as the reaction enthalpy value is negative.
Is HNO3 + Al2O3 a redox reaction ?
HNO3 + Al2O3 is not a redox reaction because none of the atoms change their oxidation state during the reaction.
Is HNO3 + Al2O3 a precipitation reaction ?
HNO3 + Al2O3 reaction is not a precipitation reaction because no solid product is obtained at the end of the reaction.
Is HNO3 + Al2O3 reversible or irreversible reaction ?
HNO3 + Al2O3 is not a reversible reaction as the product cannot be changed to reactants by any method.
Is HNO3 + Al2O3 displacement reaction ?
HNO3 + Al2O3 is a displacement reaction because the nitrate ion present in nitric acid gets transferred to aluminum nitrate in the product.
Conclusion
Al(NO3)3, which is a by-product of this reaction is a strong oxidizing agent and has wide applications which includes tanning of leather, corrosion inhibitors, petroleum refining as well as extraction of uranium.
Hello, viewers I am Mansi Sharma. I’m a medicinal chemist with a postgraduate degree. I love all facets of chemistry, and I do think that it is present everywhere, so let us explore what chemistry is all about together.
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