Write the balanced chemical equation for the neutralisation reaction between sodium hydroxide and hydrochloric acid.
The correct answer and explanation is:
The balanced chemical equation for the neutralization reaction between sodium hydroxide and hydrochloric acid is:
NaOH + HCl → NaCl + H₂O
Explanation:
Neutralization is a chemical reaction where an acid and a base react to form water and a salt. In this case, sodium hydroxide (NaOH) is a strong base and hydrochloric acid (HCl) is a strong acid. When they react, the hydroxide ion (OH⁻) from sodium hydroxide combines with the hydrogen ion (H⁺) from hydrochloric acid to form water (H₂O). The remaining ions, sodium (Na⁺) and chloride (Cl⁻), remain in solution as sodium chloride (NaCl), which is a salt.
The reaction involves the following ions:
- NaOH dissociates in water to Na⁺ and OH⁻
- HCl dissociates in water to H⁺ and Cl⁻
When they react:
- H⁺ from HCl combines with OH⁻ from NaOH to form H₂O
- Na⁺ and Cl⁻ combine to form NaCl
This reaction is a classic example of an acid-base neutralization where the acid and base neutralize each other’s properties, resulting in a neutral solution if mixed in stoichiometrically equivalent amounts.
The equation is already balanced as written because there is one sodium, one hydroxide, one hydrogen, and one chlorine atom on each side of the equation. Both sides contain equal numbers of each element, satisfying the law of conservation of mass.
Neutralization reactions like this one are important in many practical applications including:
- Controlling pH in chemical manufacturing and water treatment
- Antacid medications neutralizing stomach acid
- Laboratory titrations to determine acid or base concentrations
In summary, sodium hydroxide and hydrochloric acid react in a one-to-one mole ratio to produce sodium chloride and water, completing a simple and well-understood neutralization reaction.