15 Facts on HCl + HNO3: With Several Elements Reaction


Aqua regia is formed when HCl and HNO3 are reacted together. It is used to clean glassware and remove metals like gold, platinum, etc. Let us see facts about HCl and HNO3.

Hydrochloric acid is a colorless and odorless solution used in the protection of organic and inorganic compounds. Nitric acid is used as a strong oxidizing agent. HCl acid can be isolated in gaseous and aqueous forms, while HNO3 can be isolated in an aqueous form.

Let us discuss the product, type, and balancing of this reaction in this article.

What is the product of HCl and HNO3?

HNO3 + 3 HCl → NOCl + Cl2 + 2 H2O. Nitrosyl Chloride and Chlorine gas are the main product of HCl and HNO3.

What type of reaction is HCl + HNO3?

The reaction between HCl and HNO3 is an endothermic and redox reaction.

How to balance HCl + HNO3?

This reaction is not balanced as the number of molecules in the reactants does not equal the number of molecules in the product. Therefore so, we have to balance the equation subsequently,

  • Step 1 –  First, we should assign coefficients to all molecules present in the reaction. We use A, B, C, D, and E as we have five molecules. The reaction will look like this,
  • A HCl +  B HNO3 → C NOCl +  D Cl2 +  E H2O
  • Step 2 –    We use the labeled coefficients as alphabet reactants and products
  • H=A+ B +2E, Cl=A+C+2D, N=B+C, O=3B+C+E
  • Step 3 – Calculate the coefficient values using by Gaussian elimination method.
  • A = 3, B = 1, C = 1, D = 1, and E = 2
  • So, the balanced equation of the reaction is,
  • 3 HCl + HNO3 → NOCl + Cl2 + 2 H2O

HCl + HNO3 titration?

Titrations of HCl + HNO3 do not occur due to these reasons.

  • Two acids cannot be used for titration.
  • The pKa of HCl is -7; it is highly acidic.

HCl+ HNO3 net ionic equation?

HCl + HNO3 NOCl + Cl2 + H2O is the net Ionic equation of HCL + HNO3

HCl + HNO3 conjugate pairs

HCl, upon deprotonation, forms Cland HNO3 upon deprotonation, forms NO3+. H3O+ is the conjugate base pair of H2O.

HCl and HNO3 intermolecular forces?

Both HCl and HNO3 show Dipole-Dipole interaction forces between H and Cl and dispersion forces. Dispersion forces are attraction between nonpolar molecules.

Intermolecular force of HNO3

Is HCl + HNO3 a buffer solution?

A buffer solution is not formed as both HCl and HNO3 are strong acids. A buffer solution is formed when the solution contains an equal number of conjugate acid-base pairs (weak preferred).

Is HCl + HNO3 a complete reaction?

HNO3 + 3 HCl → NOCl + Cl2 + 2 H2O. The reaction is complete because equilibrium is reached after the common ion effect occurs.

Is HCl + HNO3 an exothermic or endothermic reaction?

HCl + HNO3 is an endothermic reaction as the enthalpy of the reaction is increased.

Is HCl+ HNO3 a redox reaction?

HCl + HNO3 is a redox reaction as there is a change in the oxidation state of Nitrogen from 5 to 2 and in the oxidation number of Chlorine from -1 to 0.

Is HCl + HNO3 a precipitation reaction?

Precipitation is not formed when HCl and HNO3 react because the cations and anions in the reaction do not combine to form insoluble ionic solids. 

Is HCl + HNO3 displacement reaction?

The reaction between HCl and HNO3 is not a displacement reaction, as NO3 does not replace Cl.

How to balance HCl + HNO3 + Pt →H2(PtCl6) + NO + H2O?

HCl + HNO3 + Pt → H2(PtCl6) + NO + H2O is not balanced as the number of molecules in the reactants does not equal the number of molecules in the product. Therefore so, we have to balance the equation subsequently,

  • Step 1 –  First, we should assign coefficients to all molecules present in the reaction. We use A, B, C, D, E, and F as we have four molecules. The reaction will look like this,
  • A HCl + B HNO3 + C Pt → D H2(PtCl6)+ E NO + F H2O
  • Step 2 – We use the labeled coefficients as alphabet reactants and products

  • H=A+ B +2D+2F, Cl=A+6D, N=B+E, O=3B+E+D, Pt =C+D

  • Step 3 – Calculate the coefficient values by the Gaussian elimination method.

  • A = 18, B = 4, C = 3, D = 3, E = 4 and F=8

  • So, the balanced equation of the reaction is,

  • 18 HCl + 4 HNO3 +3  Pt → 3H2(PtCl6) + 4 NO + 8 H2O

Which one is stronger, between HCl and HNO3?

HCl is the stronger acid as its pKa value is -7. The Pka value of HNO3 is -1.4. Lesser the pKa values more the acidic character.

Conclusion

In conclusion, the reaction between HCl and HNO3 is an endothermic and redox reaction. HCl is the stronger acid among the two and no buffer solution is formed. Nitric acid is used for doping in electrochemistry.

Ajay Sharma

Hello......I am Ajay Sharma. I have completed my Master’s degree in Organic chemistry from the Vellore Institute of Technology, Let us connect on Linkedin-www.linkedin.com/in/ajay-s-62602b1b4

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