The Chemistry Behind HNO3 + AlPO4: 15 Facts You Should Know

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Nitric acid(HNO3) is an inorganic acid that is a viscous liquid with fumaric nature, and aluminum phosphate(AlPO4) is a white powder. Let us discuss the reactions of HNO3 + AlPO4.

HNO3 is colorless but turns yellow as it absorbs the moisture from the air and can produce fumes of different colors like red or white depending on the concentration of HNO3. Whereas, AlPO4 is a berlinite mineral with a density of 2.66g/cm3 and is highly soluble in acids like HCl and HNO3.

In the following sections of the article, we are going to discuss the type of reaction, the product of the reaction with its enthalpies, and net ionic equations.

What is the product of HNO3 + AlPO4

H3PO4 (phosphoric acid ) and Al(NO3)3 (aluminum nitrate) are the products of the reaction of HNO3 + AlPO4

3HNO3 + AlPO4 = H3PO4 +  Al(NO3)3

What type of reaction is HNO3 + AlPO4

 HNO3 + AlPO4 is a double displacement reaction.

How to balance HNO3 + AlPO4

The following steps are used to balance the reaction HNO3 + AlPO4

3HNO3 + AlPO4 = H3PO4 +  Al(NO3)3

  • Name the reactants and the products with alphabets like A, B, C, and D.
  •  A 3HNO3 + B AlPO4 = C H3PO4 + D Al(NO3)3.
  • Modify the atoms with the suitable numbers required.
  • H –> A, C  ,N –>A, D  ,O –> A, B,C, D  ,Al –> B, D  ,P –> B, C.
  • Multiply the coefficients with suitable numbers.
  • A = 3 , B = 1 , C = 1 , D = 1.
  • Reduce the lowest integer value.
  • Thus, the final balanced equation is-
  • 3HNO3 + AlPO4 = H3PO4 +  Al(NO3)3

HNO3 + AlPO4 titration

HNO3 cannot be titrated with the AlPO4 because aluminum phosphate is highly soluble in HNO3 and form another acid H3PO4. Due to this, it is not possible for the chemical combination to calculate the endpoint and the unknown concentration of HNO3 + AlPO4.

HNO3 + AlPO4 net ionic equation

The net ionic equation of HNO3 + AlPO4  is –

H+ + NO-3 + Al+ + PO4 = H3+ + PO4 + Al+ + 3NO3

Following steps should be followed to write the net ionic equation.

  • Write the full reaction with the state.
  • HNO3 (l) + AlPO4 (s) = H3PO4 (l) + Al (NO3)3 (l)
  • Split the atoms, into the respective ions.
  • Thus, the net ionic equation.
  • H+ + NO-3 + Al+ + PO4 = H3+ + PO4 + Al+ + 3NO3

HNO3 + AlPO4 conjugate pairs

HNO3 + AlPO4 have the following conjugate pairs-

  • NO3- will be the conjugate base pair for acid HNO3 after the deprotonation.
  • H3PO4 will be the conjugate acid for the AlPO4 base after the protonation.

HNO3 and AlPO4 intermolecular forces

The intermolecular forces present in the reaction HNO3 + AlPO4 are –

  • Coulombic force of attraction with strong electrostatic forces of attraction and London dispersion forces are the intermolecular forces that exist between the molecules of HNO3.
  • The electrostatic force of attraction with weak Van der Waals forces of attraction is the intermolecular forces present between the molecule of AlPO4.

HNO3 + AlPO4 reaction enthalpy

Reaction enthalpy for HNO3 + AlPO4 is -193.46 KJ/mol, where–

  • The enthalpy of the formation of HNO3 is -173 KJ/mol.
  • The enthalpy of the formation of  AlPO4 is -20.46 KJ/mol.
  • Thus, the total enthalpy = (enthalpy of  formation of HNO3 ) –  (enthalpy of  formation of  AlPO4
  • = (-173 KJ/mol) – (-20.46 KJ/mol)
  • =  -193.46 KJ/mol

Is HNO3 + AlPO4 a buffer solution

HNO3 + AlPO4 is not a buffer solution as the product of the reaction is H3PO4 which is an acid itself and makes the pH of the solution less than 7 which does not specify the pH of the buffer solution.

Is HNO3 + AlPO4 a complete reaction

HNO3 + AlPO4 is a complete reaction as the products of the reaction are H3PO4 and Al(NO3)3, both are a complete complex of the specific chemical compound and cannot react further.

Is HNO3 + AlPO4 an exothermic or endothermic reaction

HNO3 + AlPO4 is an exothermic reaction as the bond dissociation of HNO3 + AlPO4 takes place a large amount of heat is evolved during the breaking of bonds which heats up the solution.

Is HNO3 + AlPO4 a redox reaction

HNO3 + AlPO4 is not a redox reaction because the oxidation states of all the reactants and products are the same throughout the reaction as there is no exchange of electrons or protons.

Is HNO3 + AlPO4 a precipitation reaction

HNO3 + AlPO4 is not a precipitation reaction because aluminum phosphate is highly soluble with acids like HNO3 because of the weak Vanderwal forces between the atoms of AlPO4.

Is HNO3 + AlPO4 reversible or irreversible reaction

HNO3 + AlPO4 is an irreversible reaction as the products are H3PO4 and Al(NO3)3 which are the complete complexes and cannot become reactants again.

Is HNO3 + AlPO4 displacement reaction

HNO3 + AlPO4 is a  double-displacement reaction as Al+ ion displaces the H+ ion from the HNO3 and the hydrogen ion also displaces the Al+ ion from AlPO4  and forms H3PO4 (phosphoric acid ) and Al(NO3)3 (aluminum nitrate).

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Displacement reaction

Conclusion

HNO3 is a powerful reagent used for the nitration of organic chemical compounds and can be used as pigments in dyes or inks and also a strong oxidizing agent whereas, AlPO4 can be used as molecular sieves and as catalysts too, and also works as good ion exchangers in a chemical reaction but it is highly toxic.