HNO3 is colourless inorganic mineral acid is good oxidizing agents, undergo redox reaction with aluminium. Let us see, how reaction proceed.
Aluminium is post transition element with atomic no. 13, show common oxidation state +3 possess covalency to form bond with varied elements. HNO3 reacts with AL to form corresponding nitrates by undergoing oxidation reduction reaction.
In this article, we will learn what will happened? When acid reacts with metal, along with its conjugate pairs and net ionic equation
What is product of HNO3 + AL
HNO3 + AL reacts to form aluminium nitrate, along with the evolution of hydrogen gas.
HNO3 + AL → AL(NO3)3 + H2
What type of reaction is HNO3 + AL
HNO3 + AL is single displacement (substitution) reaction. Displacement of AL by HNO3 is taking place in this reaction.
How to balance HNO3 + AL
The balanced reaction for HNO3 + AL is
6 HNO3 + 2 AL → 2 AL(NO3)3 + 3 H2
Here, are the following steps for balancing the reaction:
- The given reaction, that we need to balance is:
- HNO3 + AL → AL(NO3)3 + H2
- We have to represent each molecule with alphabetical terms.
- A HNO3 + B AL → C AL(NO3)3 + D H2
- To construct an equation for each of the elements (H, N, O and AL).
- In which each term denotes the number of atoms of element present in the reactant and the product side.
| Sr No. | Elements | A | B | C | D |
|---|---|---|---|---|---|
| 1 | H | 1 | 0 | 0 | 2 |
| 2 | O | 3 | 0 | 9 | 0 |
| 3 | N | 1 | 0 | 3 | 0 |
| 5 | AL | 0 | 1 | 1 | 0 |
- Enter the coefficient values in guassian elimination reaction. We have to take smallest whole number integer value after simplifying it.
- A = 6, B= 2, C= 2, D= 3
- Entering the values in alphabetical place, we will get the balanced reaction as:
- 6 HNO3 + 2 AL → 2 AL(NO3)3 + 3 H2.
HNO3 + AL titration
HNO3 + AL do not show titration. Nitric acid has strong acidic nature along with good oxidizing agent oxidizes aluminium resulting in inaccurate result in titration with aluminium. However, it does not give redox reaction too, because of absence of base in the reaction.
HNO3 + AL net ionic equation
Net ionic equation for given reaction arrives as
2 AL(S) + 6 H+(Aq) → 2 AL+3 (Aq) + 3 H2(g)
- We have to label each compound phases in balanced reaction equation.
- 2 AL (S) + 6 HNO3 (Aq) → 2 AL(NO3)3 (Aq) + 3H2 (g)
- Strong electrolytes will undergo complete ionization into ions.
- Here HNO3 and AL(NO3)3 is strong electrolyte, which gets dissociated.
- 2 AL(S) + 6 H+(Aq) + 6 NO3– (Aq) → 2 AL+3 (Aq) + 6 NO3–(Aq) + 3 H2(g).
- Remove the spectator ions NO3-, because it is present on both reactant and product side.
- 2 AL(S) + 6 H+(Aq) → 2 AL+3 (Aq) + 3 H2(g).
HNO3 + AL conjugate pairs
Conjugate pairs involve in the reaction are:
- HNO3 release H+ to give NO3– as conjugate base.
- Al being metal do not have any conjugate pairs.
- H2 accept proton to give H3O+ conjugate acid.
HNO3 + AL intermolecular forces
HNO3 + AL constitute following intermolecular forces, as follows:
- HNO3 show hydrogen bonding, London forces and dipole-dipole interaction due to polarity in its molecule because of presence of electronegative differences in its molecule.
- Aluminium has metallic bond forces of attraction due to free movements of electrons in its metallic atom.
- AL(NO3)3 have strong electrostatic intermolecular forces due to its ionic nature.
- H2 show weak London dispersion forces because of unequally distribution of electron in hydrogen atom.
HNO3 + AL reaction enthalpy
HNO3 + AL have following reaction enthalpies:
- HNO3 have enthalpy of formation -173 KJ/Mol.
- Al has enthalpy of formation 0 KJ/Mol.
- H2O have enthalpy of formation – 285 KJ/Mol.
HNO3 + AL a buffer solution
HNO3 + AL is not buffer solution because nitric acid is strong acid and buffer solution consist of weak acid and its conjugate base.
Is HNO3 + AL a complete reaction
HNO3 + AL is complete reaction because of formation of white crystalline precipitate of AL(NO3)3.
Is HNO3 + AL an exothermic or endothermic reaction
HNO3 + AL is exothermic reaction because all acid + metal reaction is taking place with evolution of heat, due to following reaction.
- In this reaction HNO3 + AL → AL(NO3)3 + H2.
- H and N bonds are broken in HNO3 molecule, while AL and HNO3 reacts to form bond and H-H bonds are formed.
- Heat has been released due to formation of more bonds than the breaking of bonds.
Is HNO3 + AL a redox reaction
HNO3 + AL is redox reaction. Here oxidation and reduction will take place by hydrogen and aluminium.
| Sr no. | Elements | Reactant | Product |
|---|---|---|---|
| 1 | H | +1 | 0 |
| 2 | N | +5 | +5 |
| 3 | O | -2 | -2 |
| 4 | AL | 0 | +3 |
- Here, H will undergo reduction by gaining 6 electrons and changing its state from +1 to 0.
- Al will undergo oxidation by changing its state from 0 to +3 by loss of 3 electrons.
Is HNO3 + AL a precipitation reaction
HNO3 + AL is precipitation reaction because of formation of AL(NO3)3 salt precipitate.
Is HNO3 + AL is reversible or irreversible
HNO3 + AL is irreversible in nature because of strong acidic behavior of nitric acid to get completely dissociated, leaving no trace ions in solution. This makes reaction not to revert back.
Is HNO3 + AL a displacement reaction
HNO3 + AL is single displacement reaction. Substitution of AL by nitric acid will take place in this reaction, giving distinct product with by products.
Conclusion
HNO3 + AL gives irreversible redox reaction to form salt with evolution of hydrogen gas. In this reaction salt aluminium nitrate is good oxidizing agents used for insulation of paper, refining of petroleum and good nitrating agents in many reactions. Heat is released during breaking and forming of bonds.
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Hello ….I am Sana Khan. A master’s student in organic chemistry from Nagpur University. I want to share my knowledge by publishing articles.