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Neutralization - Definition, Reaction, Examples, FAQs

Neutralization - Definition, Reaction, Examples, FAQs

Edited By Team Careers360 | Updated on Jul 02, 2025 04:47 PM IST

Define Neutralization

What is neutralisation?: Neutralization or neutralisation is an acid-base reaction from a chemistry point of view. The end product of the neutralisation reaction is generally water. One point to note here is that the PH of the post product of neutralisation reaction is not 7 it depends on the acidic and basic strength that are involved in this reaction.

This Story also Contains
  1. Define Neutralization
  2. With the help of base.
  3. Organic acids ( acetic acid )
  4. Neutralisation between the weak base and strong acid

acid + base (alkali) → salt + water

Note: neutralize meaning is to make it neutral chemically.

Also read -

Q – Define neutralization reaction?

Neutralization definition: Neutralisation reaction is generally a reaction between an acid and base or alkali. A neutralization reaction is an example of a double displacement reaction. Products of a neutralization reaction are always salt and water.

acid + base (alkali) → salt + water

Neutralization reaction Examples:-

HCl + NaOH → NaCl + H2O

3HNO3 + Fe(OH)3 → Fe(NO3)3 + 3H2O

Q- Neutral product definition?

The product with no charge.

Q- 10 What are neutralisation reaction examples?

Neutralization examples are,

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1639127858570

1639127858234

1639127858444

1639127858065

1639127858351

1639127858168

In general, substances involved in aqueous solutions are likely to be dissociated. Neutralisation is a quantitative type of reaction. According to Brønsted–Lowry acid-base theory neutralisation reactions is:-

AH + B → A + BH

Q- What is neutralization reaction?

Neutralization reaction is an example of acid base reaction.

In this reaction, electrical charges will be omitted from reactants and products will become neutral. Neutralization of sulfuric acid is one of its examples, it’s reaction is:-

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1639127859271

Overall: 1639127859413

It generally shows us that if acid is neutralized then there will be no hydrogen ion left in that solution to show the acidic property.

Q- How to neutralize acid?

With the help of base.

To neutralize acid we must use base and the quantity of base to be used will depend on the quantity of acid present. Or in other words, we have to use an equivalent amount of base. In the reaction or titration of acid and base, we will get a point of neutralisation that is also known as the equivalence point of that reaction. We have discussed previously that the neutralization reaction has quantitative nature; this means that this reaction will be very easily discussed in terms of the concentration of acids and bases.

As at the point of neutralization or equivalence point:-

volume (acid) × concentration (H+ ions from dissociation) = volume (base) × concentration (OH ins)

The relation between an acid with concentration C1 and a base with a concentration will be n v1 c1 = m v2 c2

Example of a base neutralization:-

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Relation of concentration, the volume will be the same as that of acid neutralisation

Note: Products of a neutralization reaction are always acid and base.

Q- What is a strong acid?

A strong acid will be fully dissociated to its 100% when dissolved in aqueous solutions.

An example will be Hydrochloric Acid (HCl)

HCl(aq) → H+(aq) + Cl(aq)

Q- What is a strong base?

A strong base will also be the one that will fully dissociate in the aqueous solution.

An example of a strong base will be:- NaOH, sodium hydroxide

NaOH(aq) → Na+(aq) + OH(aq)

Wherever there will be titration between a strong acid and strong base then we can represent that reaction like:-

H+ + OH → H2O

Explanation:- as in the reaction between hydrochloric acid and sodium hydroxide, there is no role of sodium and chloride ions, Na+ and Cl in the reaction. This type of reaction will be explained by Brønsted–Lowry definition as hydrogen ion always exists in the form of hydronium ion and that’s why neutralization reaction can be represented as:-

H3O+ + OH → H2O + H2O → 2 H2O

In the above case or any reaction where strong acid is titrated by the strong base then the solution obtained will be neutral due to the presence of no excess hydronium ion. In this case, we can say the PH to be 7. But one thing to note here is that PH is dependent on temperature also.

Q- What type of reaction is neutralisation?

A neutralization reaction is a type of exothermic reaction. And the standard enthalpy change for this reaction

H+ + OH → H2O is −57.30 kJ/mol, In which negative enthalpy represents the process to be exothermic.

Neutralisation between a weak acid and strong base:-

What is a weak acid?

The acid will not fully dissociate in an aqueous solution when dissolved. It will form equilibrium, depending on its nature.

AH + H2O ⇌ H3O+ + A

examples of weak acids are:-

Also read :

Organic acids ( acetic acid )

In this type of neutralisation reaction, the pH of the final solution will not be close to 7, as in the case of a strong acid with a strong base. Its pH at the equivalence point in the titration will depend on the dissociation constant of acid. As we know at the endpoint analytical hydrogen ion concentration will be zero and the analytical concentration of acid will be equal to the concentration of conjugate base at this point. As if we represent AH for acid and [A] = TA.

Then at equilibrium, the equation will be:-

[A][H+] = Ka[HA]; pKa = −log10Ka

In this equation, there is no talk for the solvent concentration or anything, this is because the above expression is defined on the assumption that the concentration of water ( solvent ) will be much more than dissolved acid concentration.

[H2O] >> TA.

Kw = [H+][OH]; pKw = −log10Kw

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Given below the expression for mass balance in hydrogen ion:-

TH = [H+] + Ka[A][H+] − Kw/[H+]

Here KW = self dissociation constant of water

KW = [H+][OH]

So Kw/[H+] equals hydroxide ions according to the above-mentioned equation.

As we all know at neutralization, TH is always zero.

Then we are going to multiply by [H+] on both sides the equation:-

[H+]2 + KaTA[H+]2 − Kw = 0

Rearranging and taking logarithms on both sides:-

pH = 1/2 pKw − 1/2 log (1 + TA/Ka)

In the case of dilute acid solution 1 + TA/Ka = TA/Ka

pH = 1/2 pKw - 1/2( pKA + log TA )

About the above equation;

At the point of neutralization, the Ph of the solution depends mainly on the acidic strength pKa.

At the endpoint, there is an inverse relationship between the Ph and concentration of the acid.

As in this case, there is a weak acid and strong base and pH of the base is nearer to 14 so the pH of the whole solution will rapidly increase as it reaches the endpoint. The pH of the solution is likely to be more than 7. A suitable indicator we can use to observe is phenolphthalein.

Neutralisation between the weak base and strong acid

Here also the situations are the same as that of a weak acid and strong base.

We have the equation:-

H3O+ + B ⇌ H2O + BH+

The ph of the solution at an endpoint will be dependent on the acid dissociation constant of the base, = pKa also on the base association constant, =pKb

A suitable indicator we can use in this type of solution is methyl orange.

Neutralization between weak acid and weak base

In this case, complete neutralisation is not possible.

AH + B ⇌ A + BH+

And according to this equation, we can easily observe that the concentration of the species at the endpoint is dependent on the equilibrium constant.

[A][BH+] = K[AH][B]

Given below the association constants of acid = (Ka) and base = (Kb)

A + H+ ⇌ AH; [AH] = Ka[A][H+]

B + H+ ⇌ BH+; [BH+] = Kb[B][H+]

And here K = Ka/Kb.

So according to the above theory and equations, we can easily notice that a weak base cannot neutralize weak acid and weak acid cannot neutralize a weak base.

Also, check-

NCERT Chemistry Notes:

Frequently Asked Questions (FAQs)

1. What is neutralization in chemistry?
Neutralization is a chemical reaction between an acid and a base that produces water and a salt. This process results in a solution with a pH close to 7, which is considered neutral.
2. Why is water produced in all neutralization reactions?
Water is always a product of neutralization because it forms from the combination of H+ ions from the acid and OH- ions from the base. This is a defining characteristic of acid-base neutralization reactions.
3. What is meant by "complete neutralization"?
Complete neutralization occurs when the number of moles of H+ ions from the acid exactly equals the number of moles of OH- ions from the base, resulting in a solution where neither acid nor base is in excess.
4. Can neutralization occur between two solids?
Neutralization typically occurs in aqueous solutions. While solid acids and bases can react, they usually need to be dissolved in water or another solvent for efficient neutralization to take place.
5. Can neutralization occur in non-aqueous solutions?
While most common neutralization reactions occur in water, they can also happen in non-aqueous solvents. However, the definition of acids and bases may change in these environments, affecting how neutralization is understood and observed.
6. How does a neutralization reaction differ from other types of chemical reactions?
Neutralization reactions specifically involve the combination of H+ ions from an acid with OH- ions from a base to form water. This distinguishes them from other reactions like combustion or redox reactions.
7. How does the strength of acids and bases affect neutralization?
The strength of acids and bases influences the completeness of neutralization. Strong acids and bases ionize completely, leading to more efficient neutralization, while weak acids and bases only partially ionize, affecting the reaction's endpoint.
8. Can a neutralization reaction be exothermic or endothermic?
Neutralization reactions are typically exothermic, releasing heat. The energy released comes from the formation of new bonds in water and salt molecules, which is generally more than the energy required to break the original bonds in the acid and base.
9. How does neutralization relate to the concept of pH?
Neutralization directly affects pH by combining H+ ions from acids with OH- ions from bases. As these ions react to form water, the concentration of H+ ions (which determines pH) changes, moving towards a neutral pH of 7.
10. What is a titration, and how does it relate to neutralization?
Titration is a laboratory method used to determine the concentration of an acid or base by neutralizing it with a standard solution of known concentration. It utilizes the principles of neutralization to reach an endpoint, often indicated by a color change.
11. How do polyprotic acids complicate neutralization reactions?
Polyprotic acids, which can donate multiple protons, complicate neutralization by having multiple equivalence points. Each proton is neutralized stepwise, potentially requiring different amounts of base and resulting in different salt products at each stage.
12. How can neutralization be used in everyday life?
Neutralization has many practical applications, including treating acid indigestion with antacids, neutralizing soil acidity in agriculture, treating wastewater to adjust pH levels, and in the production of various chemicals and pharmaceuticals.
13. Why doesn't the pH always end up exactly at 7 after neutralization?
The final pH may not be exactly 7 because some salts formed during neutralization can undergo hydrolysis, slightly altering the pH. Additionally, the strength of the acid and base used affects the final pH.
14. What is the role of indicators in neutralization reactions?
Indicators are substances that change color at specific pH levels. They are used to visually determine when neutralization is complete by showing a color change at the endpoint of the reaction.
15. How does the concentration of reactants affect a neutralization reaction?
The concentration of reactants affects the rate and completeness of neutralization. Higher concentrations generally lead to faster reactions and may require less volume to reach the endpoint, while lower concentrations react more slowly and require larger volumes.
16. What is meant by a "salt" in the context of neutralization?
In neutralization, a salt is the ionic compound formed from the positive ion of the base and the negative ion of the acid. For example, when hydrochloric acid reacts with sodium hydroxide, the salt produced is sodium chloride.
17. What is the significance of the heat of neutralization?
The heat of neutralization is the energy released when an acid and base react. It's an important measure of the reaction's exothermic nature and can provide information about the strengths of the acids and bases involved.
18. What is the role of water in acid-base neutralization reactions?
Water plays multiple roles in neutralization: it acts as the solvent for the reactants, participates in the reaction by accepting or donating protons, and is a product of the reaction between H+ and OH- ions.
19. What role does stoichiometry play in neutralization reactions?
Stoichiometry is crucial in neutralization as it determines the exact quantities of acid and base needed for complete neutralization. It's used to calculate the amounts of reactants and products, ensuring balanced equations and accurate predictions of reaction outcomes.
20. What is the difference between an endpoint and an equivalence point in neutralization?
The equivalence point is when the moles of acid and base are chemically equivalent. The endpoint is the point at which an indicator changes color, which may not exactly coincide with the equivalence point but is used as a practical measure in titrations.
21. How does temperature affect neutralization reactions?
Temperature can influence the rate of neutralization reactions. Higher temperatures generally increase reaction rates by providing more kinetic energy to the reacting particles, leading to more frequent and effective collisions.
22. How does the concept of Le Chatelier's principle apply to neutralization reactions?
Le Chatelier's principle applies to neutralization in equilibrium systems. If products (like water or salt) are removed or reactants are added, the equilibrium shifts to counteract the change, affecting the completeness of neutralization.
23. What are some limitations of using indicators in neutralization reactions?
Limitations of indicators include: they may not change color exactly at the equivalence point, some may interfere with the reaction, they can be affected by temperature and other ions, and they may not be suitable for colored or turbid solutions.
24. How do neutralization reactions in biochemistry differ from those in general chemistry?
In biochemistry, neutralization often involves more complex molecules like amino acids and proteins. These reactions can be affected by the biological environment, pH-dependent protein structures, and enzymatic activities, making them more complex than simple acid-base neutralizations.
25. What are some advanced techniques used to study neutralization reactions?
Advanced techniques include potentiometric titration for precise pH measurement, calorimetry to measure heat of neutralization, spectroscopic methods to observe species during reaction, and computational modeling to predict reaction outcomes and understand molecular-level interactions.
26. What are some emerging areas of research related to neutralization in chemistry?
Emerging research areas include: developing more efficient and environmentally friendly neutralization methods for industrial waste treatment, exploring neutralization in extreme conditions (like deep-sea vents or space environments), and investigating the role of neutralization in the origins of life and prebiotic chemistry.
27. What is a buffer solution, and how does it relate to neutralization?
A buffer solution resists changes in pH when small amounts of acid or base are added. It's related to neutralization because it often contains a weak acid and its conjugate base (or vice versa), which can neutralize small additions of H+ or OH- ions.
28. How do weak acid-strong base neutralizations differ from strong acid-strong base neutralizations?
Weak acid-strong base neutralizations result in a basic solution at the equivalence point due to the hydrolysis of the salt formed. In contrast, strong acid-strong base neutralizations result in a neutral solution (pH 7) at the equivalence point.
29. How does the concept of acid-base strength relate to neutralization?
Acid-base strength affects neutralization by influencing the extent of ionization. Strong acids and bases ionize completely, leading to more straightforward neutralization, while weak acids and bases only partially ionize, resulting in more complex equilibria.
30. What is a neutralization curve, and what information does it provide?
A neutralization curve is a graph showing pH changes during titration. It provides information about the strengths of the acid and base, the equivalence point, and buffer regions. The curve's shape varies depending on the strengths of the acid and base involved.
31. How does the presence of other ions affect neutralization reactions?
Other ions can affect neutralization by participating in side reactions, altering the ionic strength of the solution, or affecting the solubility of products. This can influence the reaction rate, equilibrium, and the final pH of the solution.
32. What is the significance of the neutralization constant?
The neutralization constant (Kn) represents the equilibrium constant for the reaction between H+ and OH- ions to form water. It's important because it determines the extent of neutralization and is related to the ion product of water (Kw).
33. How do amphoteric substances interact with neutralization processes?
Amphoteric substances can act as both acids and bases, depending on the reaction conditions. In neutralization, they can participate on either side of the reaction, potentially complicating the process and affecting the final pH.
34. What is the relationship between neutralization and acid-base titrations?
Acid-base titrations are practical applications of neutralization reactions. They use the principles of neutralization to determine unknown concentrations of acids or bases by reacting them with standard solutions of known concentration until reaching an endpoint.
35. How does the concept of conjugate acid-base pairs relate to neutralization?
Conjugate acid-base pairs are formed during neutralization. The acid donates a proton to become its conjugate base, while the base accepts a proton to become its conjugate acid. Understanding these pairs helps predict the behavior of the resulting solution.
36. What is meant by "back titration" in the context of neutralization?
Back titration is a technique where an excess of standard solution is added to a sample, and then the excess is titrated with another standard solution. It's useful for samples that react slowly or are insoluble, allowing for indirect neutralization and concentration determination.
37. How do neutralization reactions in organic chemistry differ from those in inorganic chemistry?
In organic chemistry, neutralization often involves more complex molecules and can include reactions between organic acids and bases. These reactions may have different kinetics, equilibria, and product formations compared to simpler inorganic acid-base neutralizations.
38. What is the importance of understanding neutralization in environmental science?
Understanding neutralization is crucial in environmental science for managing pH levels in ecosystems, treating acid rain effects, wastewater management, and soil treatment. It helps in developing strategies to mitigate environmental acidification or basification.
39. How does the presence of a common ion affect neutralization reactions?
The common ion effect can influence neutralization by shifting the equilibrium of weak acids or bases. This can affect the pH at which neutralization occurs and may require adjustments in calculations and experimental procedures.
40. How does neutralization relate to the concept of hydrolysis?
Hydrolysis can occur after neutralization when the salt produced reacts with water. This can lead to solutions that are not perfectly neutral, as the hydrolyzed ions can affect the pH. Understanding this helps explain why some neutralization reactions don't result in a pH of exactly 7.
41. What is the significance of the neutralization energy in chemical processes?
Neutralization energy is the heat released during neutralization. It's significant in understanding reaction thermodynamics, designing chemical processes, and in applications like calorimetry. The amount of energy released can indicate the strengths of the acids and bases involved.
42. What role does neutralization play in the formulation of pharmaceuticals?
Neutralization is crucial in pharmaceutical formulations for adjusting pH, creating salt forms of drugs for better solubility or stability, and in the production of buffer systems. It's essential for optimizing drug efficacy, stability, and bioavailability.
43. How does the concept of Lewis acids and bases extend our understanding of neutralization?
The Lewis concept extends neutralization beyond proton transfer to include electron pair donation. This broader definition includes reactions where no H+ or OH- ions are involved, such as the formation of complex ions, which can be considered a form of neutralization in some contexts.
44. What is the importance of understanding partial neutralization in chemical analysis?
Partial neutralization is important in analyzing polyprotic acids or mixtures of acids/bases. It helps in identifying individual components, understanding stepwise dissociation, and in designing buffer solutions. It's crucial for accurate pH control in various chemical and biological systems.
45. How do neutralization reactions contribute to the understanding of acid-base equilibria?
Neutralization reactions provide practical examples of acid-base equilibria in action. They demonstrate how the concentrations of H+ and OH- ions change, how equilibrium shifts occur, and how factors like acid/base strength and concentration affect the final equilibrium state.
46. How does the concept of neutralization apply in non-aqueous acid-base chemistry?
In non-aqueous systems, neutralization is based on the solvent system's definition of acids and bases. It may involve proton transfer or other forms of electron pair donation/acceptance. The concept extends to reactions in organic solvents, molten salts, or even gas-phase acid-base interactions.
47. What is the relationship between neutralization and the formation of coordination compounds?
While not traditionally considered neutralization, the formation of coordination compounds can be viewed as a Lewis acid-base neutralization. The metal ion (Lewis acid) accepts electron pairs from ligands (Lewis bases), neutralizing their reactive potential and forming stable complexes.
48. How does neutralization relate to the concept of hard and soft acids and bases (HSAB)?
The HSAB concept helps predict the outcomes of acid-base reactions, including neutralization. It explains why certain acids and bases react more readily with each other, influencing the strength of the neutralization reaction and the stability of the resulting products.
49. What role does neutralization play in understanding and controlling chemical equilibria?
Neutralization reactions provide practical examples of shifting chemical equilibria. By adding acids or bases, the equilibrium can be manipulated, demonstrating principles like Le Chatelier's. This understanding is crucial in controlling industrial processes, environmental systems, and biochemical reactions.
50. How does the study of neutralization contribute to the development of new materials and technologies?
Understanding neutralization is vital in developing new materials like smart polymers that respond to pH changes, self-healing materials that neutralize corrosive substances, and advanced drug delivery systems that release medications in response to specific pH environments in the body.

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