Please help !!!!

The acid impurity in your unknown was benzoic acid.
a) Write an equation for the reaction that occurs during the NaOH extraction.
b) Write an equation for the reaction that occurs after the addition of HCL. Thanks.

acid + base = salt + water

HBz + NaOH ==> NaBz + H2O
NaBz + HCl ==> HBz + NaCl
Benzoic acid is C6H5COOH and it is the right most H that is involved in the reaction. I have let Bz stand for C6H5COO.
The idea behind this is that benzoic acid reacts with NaOH to produce the sodium salt which is quite soluble in water. That allows you to separate the benzoic acid from the reactants in the procedure. After separation, you want to regenerate the benzoic acid so you add HCl and that re-precipitates the benzoic acid and you can extract that into an organic solvent.

a) The reaction that occurs during the NaOH extraction is as follows:

Benzoic acid (unknown) + Sodium hydroxide (NaOH) → Sodium benzoate (soluble) + Water

C6H5COOH + NaOH → C6H5COONa + H2O

b) The reaction that occurs after the addition of HCl is as follows:

Sodium benzoate (soluble) + Hydrochloric acid (HCl) → Benzoic acid (precipitate) + Sodium chloride (soluble)

C6H5COONa + HCl → C6H5COOH + NaCl

Sure! I can help you with that. To write the equations for the reactions that occur during the NaOH extraction and after the addition of HCl, we need to understand the chemistry behind it.

During the NaOH extraction, the benzoic acid is converted into its water-soluble sodium salt, sodium benzoate. The reaction can be represented by the following equation:

C6H5COOH (benzoic acid) + NaOH (sodium hydroxide) → C6H5COONa (sodium benzoate) + H2O

In this reaction, the acidic proton (H+) from the carboxylic acid group (COOH) in benzoic acid is replaced by the sodium ion (Na+), forming the sodium salt.

After the addition of HCl, the sodium benzoate is converted back into the original benzoic acid. This process is called acidification or neutralization. The equation for this reaction is as follows:

C6H5COONa (sodium benzoate) + HCl (hydrochloric acid) → C6H5COOH (benzoic acid) + NaCl (sodium chloride)

In this reaction, the sodium ion from sodium benzoate is replaced by the hydrogen ion (H+) from hydrochloric acid, forming benzoic acid again. Sodium chloride (NaCl) is the byproduct formed in this reaction.

These equations represent the reactions that occur during the NaOH extraction and after the addition of HCl to convert the impurity, benzoic acid, back into its original form.