13 Facts on HCl + NaOH: What, How To Balance & FAQs

HCl + NaOH reaction is a very common and basic chemical reaction like an introduction to ionic chemistry. Let us analyze this reaction and its results in this article.

Hydrochloric acid (HCl) is a strong mineral acid with a pungent and strong smell. It is also corrosive. On the other hand, sodium hydroxide (NaOH) is a white powdery solid mineral base that like HCl is corrosive.

The reaction between HCl and NaOH is between a strong acid and strong base which in turn will give a neutral ionic compound instead of showing an inclination to either acidity or basicity. Let us inspect various information related to their reaction like the product, type, titration, etc.

What is the product of HCl and NaOH?

HCl + NaOH reaction produce NaCl which is salt and H₂O as a byproduct with the advent of heat. HCl and NaOH being mineral acid and base respectively can undergo complete dissociation of their respective ions.

The overall mechanism of the reaction is:

HCl = H⁺ + Cl^–

NaOH = Na⁺ + OH^–

H⁺ + Cl^– + Na⁺+ OH^–= NaCl + H₂O

What type of reaction is HCl + NaOH?

HCl + NaOH is a neutralization reaction which is between an acid and a base resulting in the production of neutral salt and water. HCl + NaOH reaction is also a double displacement reaction because the individual cation and anions of the reactant are exchanged to maintain equilibrium.

How to balance HCl + NaOH?

The balancing of any chemical equation implies the existence of equilibrium in the number of molecules at both the reactant and the product sites. As far as HCl + NaOH reaction is concerned then it is already balanced in an equimolar manner.

HCl + NaOH = NaCl + H₂O

HCl + NaOH titration

Apparatus used

Burette, Pipette, 250 ml titration flask, beaker, iron stand, glass rod, filter funnel.

The indicator used

Methyl orange or phenolphthalein can be used as an indicator for strong acid Vs strong base reaction for analyzing the endpoint of the reaction.

Process

Fill the burette with NaOH and add HCl to the titration flask with the help of a pipette. Add an indicator in the titration flask as well. Now pour NaOH drop by drop from the burette to achieve the endpoint which is the transparent neutral solution in this case. Note the consonant reading.

HCl + NaOH net ionic equation

To determine the net ionic equation following steps should be implemented:

Dissociation of the two reactants NaOH and HCl into their respective ions.
Mix both solutions where they will dissolve each other due to the presence of water molecules. The rest of the HCl and NaOH ions will be spectator ions.
The complete ionic equation will be H⁺ + Cl^– + Na⁺ + OH^–= Na⁺ + Cl^–+ H₂O
Remove the spectator ions so the net ionic equation will be H⁺ + OH^–= H₂O

HCl + NaOH conjugate pairs

In HCl + NaOH reaction HCl and H₂O are proton donors and NaOH and NaCl are proton acceptors maintaining the equilibrium of the reaction. Conjugate pairs are easily observable in acid-base reactions where there is proton donation and proton acceptance.

HCl and NaOH intermolecular forces

In HCl, there are 2 types of intermolecular forces: dipole-dipole and London dispersion forces. Out of both dipole-dipole is stronger because of the high electronegativity of Cl.
As far as NaOH is concerned it is governed by the ion-dipole interactions which are the strongest of all the intermolecular interactions as they can generate instantaneous dipole.

HCl + NaOH reaction enthalpy

The reaction enthalpy of HCl + NaOH is -55.84 KJ/mol. It is also called enthalpy of neutralization which is the same for every strong acid and strong base reaction. The negative sign in the enthalpy implies the exothermic reaction.

Is HCl + NaOH a buffer solution?

HCl + NaOH reaction does not form a buffer solution. There is simple mixing which results in salt formation. For buffer formation, there should be a weak acid or weak base for pH maintenance. But in this scenario, both acid and base are strong which neutralizes each other.

Is HCl + NaOH an exothermic or endothermic reaction?

HCl + NaOH is an exothermic reaction because the reactants are trying to balance out each other which eventually releases heat. This leads to the heating of the reaction mixture which is then transferred to the surroundings to cool the mixture. It can be evident from the warm reaction beaker.

Is HCl + NaOH a redox reaction?

HCl + NaOH is not a redox reaction because here the oxidation state of the reactant side is equal to that of the product side thereby nullifying the oxidation-reduction effect.

Is HCl + NaOH a precipitation reaction?

HCl + NaOH is not a precipitation reaction as there is no insoluble compound formation at the bottom of the reaction mixture. In HCl + NaOH reaction, the product NaCl is a salt that dissolves in water instead of precipitation out.

Is HCl + NaOH reversible or irreversible reaction?

HCl + NaOH, is an irreversible reaction which implies that the product formation cannot be reversed to reactants. This is because the equilibrium constant of the reaction is very large which strongly favors the forward reaction because of the high ionization of the strong acid and strong base.

Is HCl + NaOH displacement reaction?

HCl + NaOH is a double displacement reaction where there is an interchange of cationic parts Na and H with the anionic parts Cl and OH to produce salt NaCl and H₂O. A double displacement reaction of HCl + NaOH takes place in an aqueous medium which makes no difference whether it precipitates or not.

Conclusion

In a nutshell HCl + NaOH is a very basic and popular example of a neutralization reaction which is the basis of salt formation. Salt formation is the basis of life’s existence and has varied applications both chemically and biologically.