Neutralization

‘Neutralisation’ or Neutralization definition is a chemical reaction in which an acid reacts with a base or alkali to form water and salt. In the reaction, the H+ ions of Hydrogen in an acid combine with the OH- (hydroxide) ions of the basic solution, and this is how water is formed from neutralization. The neutralized solution usually has a ph seven value, but the pH value can differ depending on the acidic or basic strength of the reactants. When the neutralization process takes place between a strong acid and a weak base, then the pH level would be less than 7, and conversely for a reaction between a strong base and weak acid will result in a solution of pH value more than 7.  

It is helpful to remember a few names of strong acids and strong bases so that while solving a chemical reaction one can quickly identify these.

List of Strong Acids and Strong Bases

Application of Neutralization

The applications of neutralization are the following:

• Neutralization is used in wastewater treatment to reduce the effluent created damage.

• The process in which antacid tablets work to minimize the acidic reaction in the stomach is also the neutralization reaction. The antacids usually contain Aluminum Hydroxide, Sodium Hydroxide and Magnesium Hydroxide which are bases.

• For determination of unknown concentration, the process of neutralization is used for chemical titration by analyzing the acids or bases. 

• The home remedy for a bee sting is baking soda application of the stung area, and this is also a basic application of neutralization because the bee sting contains formic acid and a base like baking soda neutralizes the reaction to reduce the pain and itching. 

• On the other hand, a wasp sting is basic and to minimize the pain vinegar is applied to the affected area so that it can neutralize the acidic reaction of the wasp’s sting venom.

• The pH of the soil is also controlled using the application of neutralization because plants cannot grow in very acidic or excessive basic soil. A secure method to control the acidic nature of the soil is by adding bases like CaCo3, CaO, ash of burnt wood, etc.

• NH4OH is used in the rubber industry to prevent the coagulation of latex. The basic ammonia solution can neutralize lactic acid to stop thickening.

• Toothpaste is not only used to maintain our mouth’s hygiene but also used as a neutralizing agent for the effects of the food we eat. Most food that we consume is acidic in nature, and the acidic effect of the food reacts on the enamel or the calcium phosphate layer of our teeth and results in the formation of the cavity. It is the basic quality of toothpaste that prevents cavity formation by neutralizing the reaction.

Neutralization Reaction

The Neutralization process in the reaction form can be expressed as the following:

Acid + Base → Salt + Water

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Some Popular Neutralization Examples are :

• HCl + NaOH → NaCl + H2O

• 2HNO3 + Ba(OH)2 → Ba(NO3)2 + 2H2O

• H2CO3 +2KOH → K2CO3 + 2H2O

• 2H3PO4 + 3Ca(OH)2 → Ca(PO4)2 + 6H2O

• 3HNO3 + Fe(OH)3 →Fe(NO3)3 + 3H2O

Solved Examples

Some neutralization examples of the problem with the solution are:

1. To titrate 45 mL of 0.0452 M HNO3, how many mL of 0.0955M Ba(OH)2 solution is required?

From the given problem we can assume that M₁ = 0.0452M, M₂ = 0.0955, V₁ = 45mL.

The equation or formula to solve this problem is, 

M₁V₁ = M₂V₂

V₂ = \[\frac{M_{1}V_{1}}{M_{2}}\] = \[\frac{(0.0452)\times (45)}{0.0955}\] = 21.2 mL

2. CH3COOH (aq) + NaOH (s) ⇋ (Na+) + (CH3COO-) + H2O, In this reaction the resultant salt will have a greater, less, or a pH level equal to 7?

From the equation, we can see that the strong base NaOH is getting neutralized by the weak acid CH3COOH; hence the pH level will be higher than 7.

Did You Know?

The neutralization reaction can also occur even if one reactant is not in the aqueous phase. An example of that would be the reaction between the acid the aqueous state HCl and the base or alkali component that is solid like Fe(OH)3. The equation of the neutralization reaction is,

3HCl (aqueous) + Fe(OH)3 (solid) → FeCl3 (aqueous) + 3H2O (liquid)

Since we know that Fe(OH)3 being a component of rust is not soluble in nature, then we can also realize from the above reaction that rust cleaning solutions contain acids. The neutralization reaction between the rust component and an acid like HCl can produce products that are soluble and can be washed away.

Neutralisation

Neutralisation can be defined as the chemical reaction which happens when an acid and a base are mixed together. This can be done by making a neutral solution which is made by adding the right amount of acid and base. The acid and the base can be said to cancel each other and this reaction is carried out gradually. It is an exothermic reaction, i.e., the mixture of the reaction releases heat when the reaction is occurring. For example, in water, a neutralisation reaction occurs due to the absence of excess hydrogen or hydroxide ions in the solution. The pH of such solutions which have undergone neutralisation reactions depends on the reactants’ acid strength. One of the examples of such a reaction is acid rain.

Mechanism of the Reaction

The mechanism of such a reaction can be understood by taking the example of an acid-base reaction. In neutralization, the H+ or hydrogen-ion of acid is canceled out or neutralized by the OH- ion (hydroxyl ion) present in the base. When all the hydrogen ions present in the acid are neutralized by the same amount of hydroxyl ions of the base then complete neutralisation is said to occur.

Conclusion

The study notes on the Chemistry topic Neutralisation covers all the important aspects of the topic including its definition, the chemical reactions involved in the process, and its applications. The notes also provide solved numerical problems using the associated formulae.