1. Ionic Dissociation:
- Sodium hydroxide (NaOH) is a strong base that completely dissociates in water, forming sodium (Na+) and hydroxide (OH-) ions.
- Hydrochloric acid (HCl) is a strong acid that completely dissociates in water, forming hydrogen (H+) and chloride (Cl-) ions.
2. Neutralization Reaction:
- When the two solutions are mixed, hydrogen ions (H+) from hydrochloric acid react with hydroxide ions (OH-) from sodium hydroxide to form water molecules (H2O).
- The overall chemical equation for the neutralization reaction is:
NaOH(aq) + HCl(aq) -> NaCl(aq) + H2O(l)
3. Formation of Sodium Chloride:
- As the reaction proceeds, sodium ions (Na+) from sodium hydroxide and chloride ions (Cl-) from hydrochloric acid combine to form sodium chloride (NaCl), which is a neutral salt.
- Sodium chloride dissolves in water and dissociates into its respective ions.
4. Heat Release:
- The neutralization reaction is exothermic, meaning it releases heat. The released heat causes the solution temperature to rise, and the reaction mixture may feel warm to the touch.
5. pH Change:
- Before mixing, sodium hydroxide solution has a high pH (basic) due to the presence of hydroxide ions. Hydrochloric acid has a low pH (acidic) due to the presence of hydrogen ions.
- After neutralization, the pH of the resulting solution becomes neutral (pH = 7) because the hydrogen ions and hydroxide ions have been consumed in equal amounts.
6. Salt Formation and Solution Conductivity:
- The formed sodium chloride (NaCl) increases the conductivity of the solution. This is because sodium chloride, like other salts, dissociates into ions in water, allowing the solution to conduct electricity.
In summary, mixing sodium hydroxide solution and hydrochloric acid results in a neutralization reaction, forming water and sodium chloride as products. The reaction releases heat and changes the solution's pH to neutral. The resulting solution contains sodium and chloride ions, which contribute to its increased conductivity.
