Neutralization - Definition, Reaction, Examples, FAQs

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.

acid + base (alkali) → salt + water

Note: neutralize meaning is to make it neutral chemically.

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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,

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:-

Overall:

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:-

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:-

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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⁻] = T_A.

Then at equilibrium, the equation will be:-

[A⁻][H⁺] = K_a[HA]; pK_a = −log₁₀K_a

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] >> T_A.

K_w = [H⁺][OH⁻]; pK_w = −log₁₀K_w

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

T_H = [H⁺] + K_a[A⁻][H+] − K_w/[H⁺]

Here K_W = self dissociation constant of water

K_W = [H⁺][OH⁻]

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

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

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

[H⁺]² + K_aT_A[H⁺]² − K_w = 0

Rearranging and taking logarithms on both sides:-

pH = 1/2 pK_w − 1/2 log (1 + T_A/K_a)

In the case of dilute acid solution 1 + T_A/K_a = T_A/K_a

pH = 1/2 pK_w - 1/2( pK_A + log T_A )

About the above equation;

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

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, = pK_a also on the base association constant, =pK_b

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 = (K_a) and base = (K_b)

A⁻ + H⁺ ⇌ AH; [AH] = K_a[A⁻][H⁺]

B + H⁺ ⇌ BH⁺; [BH⁺] = K_b[B][H⁺]

And here K = K_a/K_b.

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.

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