9 Facts on CH3COOH+ NaOH :With Several Elements Reaction

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In this article, “hc2h3o2 + naoh”, the product and type of this reaction with some relevant topics are discussed briefly.

The mixture of acetic acid (CH3COOH) and sodium hydroxide (NaOH) works as a solution of weak acid and strong base and the products of this reaction are sodium acetate (CH3COONa) and water (H2O). This is an example of acid neutralization reaction with weak acid and strong base.

Let’s focus on the following topics related to the above subjects.

What happens when CH3COOH reacts with NaOH?

The reaction between acetic acid and sodium hydroxide is an example of neutralization reaction. CH3COOH or acetic acid is a weak acid because it cannot be dissociated 100% in aqueous solution. But NaOH is a strong acid due to complete dissociation in aqueous solution.

  • CH3COOH = CH3COO– + H+
  • NaOH = Na+ + OH–

When NaOH is added into the beaker containing CH3COOH, the acetate ion (CH3COO–) which are formed in the dissociation of CH3COOH, reacts with the sodium cation (Na+) and form sodium acetate (CH3COONa) and water (H2O).

CH3COOH + NaOH = CH3COONa + H2O.

It is also an example of double displacement reaction because both the reactants exchange ions with each other to obtain the sodium acetate salt and water.

As acetic acid is a weak acid and sodium hydroxide is a strong base, thus the Ph of the solution will be basic in nature (pH is greater than 7).

What kind of reaction is CH3COOH + NaOH?

This is the reaction between weak acid and strong base and any reaction involving acid and base will be an example of neutralization reaction. Neutralization reaction is one type chemical of reaction in which acid and base reacts with each other in a quantitative amount to form salt and water.

The above reaction is a neutralization reaction between a weak acid (CH3COOH) and strong base (NaOH). A weak acid CH3COOH can’t be fully dissociated in aqueous solution.

CH3COOH + H2O = H3O+ + CH3COO–.

The pH of the neutralization reaction will depend upon the following reaction-

CH3COOH + OH– = H2O + CH3COO–.

And the acid dissociation constant (ka) of acetic acid.

The formula of calculating the pH of the neutralization reaction between a strong base and weak acid is-

pH = ½ (pkw + log ka + log c)

In the above reaction, pkw = 14 and ‘c’ is the concentration of salt (CH3COONa).

How to balance CH3COOH + NaOH?

To balance any chemical reaction, firstly the unbalanced equation should be written. In this above example the unbalanced equation will be-

CH3COOH + NaOH = CH3COONa + H2O.

Now break the total unbalanced reaction into two parts-

  • Acid part- CH3COOH = CH3COO– + H+ ———— 1
  • Base part – NaOH = Na+ + OH– ————- 2

Multiply the 1 and 2 numbered equation with 1 and we get-

CH3COOH + NaOH = CH3COONa + H2O.

There is no need to multiply the above two equations with any other integer because the balanced form of the reaction is obtained correctly.

Titration of acetic acid with NaOH

For a titration reaction the following compounds are required-

  1. Acid
  2. Base
  3. An indicator.

In this titration reaction between acetic acid and sodium hydroxide, basically phenolphthalein indicator is used to detect the endpoint.

During the titration of CH3COOH and NaOH, acid is taken in a conical flask and the base is taken into a burette. The base is added by drop wise to the acid + indicator solution. In this titration, the addition of OH– ion (coming from NaOH) neutralizes the H+ ion of the acid. But in this solution kept in conical flask, the concentration of H+ ion is very low due to partially dissociation of weak acetic acid.

Thus, further adding of OH– ion from NaOH increases the pH of the solution abruptly. The Ph of the titration lies between 6.5 to 10 and pH of the phenolphthalein ranges from 8.2 to 10. Thus, phenolphthalein is an appropriate indicator used for this titration of weak acid and strong base.

hc2h3o2 + naoh
Titration between a weak acid and strong base.
Image Credit : Wikimedia Commons.

CH3COOH and NaOH Buffer Equation

To decide whether it is buffer solution or not first we have to clear the concept of buffer solution. Buffer is a solution of weak acid and its conjugate base or weak base and its conjugate acid in which the Ph can’t be altered very much after adding a certain amount of acid and base.

Thus, from the definition of buffer, it is clear that the mixture of CH3COOH and NaOH is not a buffer. Because it is a mixture of weak acid and strong base not the weak acid and its conjugate base or weak base and its conjugate acid.

Buffer solutions can be two types-

  1. Acidic buffer, for example mixing of CH3COOH and CH3COONa
  2. Basic buffer, for example mixing of NH4Cl and NaOH.

Molarity of acetic acid in NaOH

The balanced net equation of acetic acid and NaOH is-

CH3COOH + NaOH = CH3COONa + H2O.

This equation tells that the mole ration of acetic acid of NaOH is 1:1. It means equal amount of acetic acid is required for the titration with sodium hydroxide to obtain sodium acetate and water.

Conclusion

In the reaction of acetic acid with sodium hydroxide, sodium acetate and water are obtained as products. This is not a buffer solution but a mixture of weak acid and strong base.