Applications of Neutralization Reactions in Everyday Life and Industrial Processes

Everyday Life Applications

1. Antacid Tablets:

• Problem: Many people suffer from acid reflux, a condition where stomach acid (primarily hydrochloric acid, HCl) regurgitates into the lower oesophagus, causing a burning sensation.

• Solution: To alleviate the symptoms, antacid tablets are used. These tablets contain basic compounds like magnesium hydroxide (Mg(OH)₂) or aluminium hydroxide (Al(OH)₃), which undergo neutralization reactions with stomach acid, increasing the pH and reducing irritation.

• Example Reactions: 

  • Magnesium Hydroxide:
    Mg(OH)₂(s) + 2HCl(aq) → MgCl₂(aq) + 2H₂O(l)

  • Aluminium Hydroxide:
    Al(OH)₃(s) + 3HCl(aq) → AlCl₃(aq) + 3H₂O(l)

2. Preventing Tooth Decay:

• Problem: Acids in the mouth, especially from food and drink, can erode tooth enamel and lead to decay.

• Solution: Toothpaste is weakly alkaline and neutralizes these acids. It contains mild bases such as calcium carbonate (CaCO₃), aluminium oxide (Al₂O₃), and magnesium carbonate (MgCO₃).

• Example Reaction: 

  • Calcium Carbonate with Acid:
    CaCO₃(s) + 2HX(aq) → CaX₂(aq) + H₂O(l) + CO₂(g)
    This neutralizes acids in the mouth, helping prevent damage to teeth.

3. Baking (Baking Soda):

• Problem: During baking, dough must rise to become light and fluffy.

• Solution: Baking soda (sodium bicarbonate, NaHCO₃) is a key ingredient in baking powder. It reacts with acidic ingredients in the dough, producing carbon dioxide (CO₂) gas. This gas causes the dough to expand and rise.

• Example Reaction: 

  • NaHCO₃(s) + HX(aq) → NaX(aq) + H₂O(l) + CO₂(g)

Industrial Applications

1. Acid and Base Spills:

• Problem: Spills of acids or bases in industrial settings can be hazardous, as both are corrosive and can cause significant damage to the environment or human health.

• Solution: Neutralization is used to neutralize these spills. The choice of neutralizing agent depends on the nature of the spill (acidic or basic), the extent of the spill, and the concentration of the acid or base.

• Desirable Characteristics of Neutralizing Agents:

  • Cheap and safe for easy handling.

  • Weakly acidic or basic to be safer in case of overuse.

  • Solid powders are preferred as they are easier to store and apply, and they don’t spread the spill further.

  • Amphiprotic substances (substances that can act as either an acid or base) are useful when it’s unclear whether the spill is acidic or basic.

• Example Neutralizing Agent:

  • Sodium bicarbonate (NaHCO₃) is commonly used for neutralizing both acids and bases. It’s cheap, stable, and amphiprotic. It also releases gas (CO₂) when reacting with acid, which indicates the progress of the neutralization reaction.

2. Treatment of Wastewater:

• Problem: In industries like semiconductor manufacturing, wastewater can contain harmful acids such as hydrofluoric acid (HF), which need to be neutralized to prevent environmental contamination.

• Solution: Neutralization of HF can be achieved using bases such as sodium hydroxide (NaOH) or calcium hydroxide (Ca(OH)₂). Calcium hydroxide is especially useful as it forms a solid precipitate (CaF₂), which can be easily removed from the wastewater.

• Example Reaction: 

  • Ca(OH)₂(aq) + 2HF(aq) → CaF₂(s) + 2H₂O(l)

  • For basic wastewater, weak acids like citric acid (C₆H₈O₇) or acetic acid (CH₃COOH) are used to neutralize the alkalinity.