Understanding the Reaction
* Benzoic acid (C₆H₅COOH) is a weak acid.
* Dichloromethane (CH₂Cl₂) is an organic solvent that is unreactive in this case.
* Sodium hydroxide (NaOH) is a strong base.
When you add sodium hydroxide to the solution, the following reaction occurs:
C₆H₅COOH (benzoic acid) + NaOH (sodium hydroxide) → C₆H₅COO⁻Na⁺ (sodium benzoate) + H₂O (water)
Explanation
1. Deprotonation: The hydroxide ions (OH⁻) from sodium hydroxide react with the benzoic acid molecules, removing a proton (H⁺) from the carboxylic acid group (-COOH). This forms a benzoate ion (C₆H₅COO⁻).
2. Salt Formation: The benzoate ion then combines with the sodium ion (Na⁺) from the sodium hydroxide to form sodium benzoate (C₆H₅COO⁻Na⁺).
3. Water Formation: The proton removed from the benzoic acid combines with the hydroxide ion to form water (H₂O).
Key Observations
* Solubility: Benzoic acid is not very soluble in water but is soluble in dichloromethane. Sodium benzoate is more soluble in water than in dichloromethane.
* Phase Separation: As the reaction proceeds, you will likely see two layers forming: a lower layer of dichloromethane with any unreacted benzoic acid and an upper layer of water containing the dissolved sodium benzoate.
Overall: The product of the reaction is sodium benzoate (C₆H₅COO⁻Na⁺). The reaction is a simple acid-base neutralization reaction.
