Common bases

Definition of a Base

• A base is a substance that can neutralise acids to form salt and water.
• Bases that are soluble in water are called alkalis.
• They have a $pH$ greater than 7 and often feel slippery to the touch.

Strength of Bases

• Bases are classified as strong or weak based on how completely they dissociate in water:
  • Strong bases dissociate fully, releasing a high concentration of hydroxide $(OH⁻)$ ions.
  • Weak bases partially dissociate, releasing fewer $OH⁻$ ions.

Common Bases and Their Uses

Strong Bases

1. Sodium Hydroxide (NaOH)$$ – Caustic Soda

• Uses:
• Soap and detergent production.
• Drain cleaner to dissolve grease.
• Human hair removal in chemical treatments.

2. Potassium Hydroxide $(KOH) –$ Caustic Potash

• Uses:
• Soap production.
• Battery electrolyte in alkaline batteries.

3. Magnesium Hydroxide $(Mg(OH)₂)$

• Uses:
• Antacids (Milk of Magnesia) to neutralise stomach acid.
• Wastewater treatment to neutralise acidic waste.

4. Calcium Hydroxide $(Ca(OH)₂) –$ Slaked Lime

• Uses:
• Water purification to remove impurities.
• Soil treatment to neutralise acidity.
• Cement and plaster production.

Weak Bases

1. Sodium Carbonate $(Na₂CO₃) –$ Washing Soda

• Uses:
• Soap and glass manufacturing.
• Softens hard water in detergents.

2. Calcium Carbonate $(CaCO₃) –$ Limestone

• Uses:
• Main component in chalk, cement, and marble.
• Antacid to relieve acid indigestion.

3. Ammonia $(NH₃)$

• Uses:
• Fertiliser production.
• Industrial cleaning agent.

4. Sodium Bicarbonate $(NaHCO₃) –$ Baking Soda

• Uses:
• Baking – causes dough to rise.
• Mild antacid to relieve heartburn.
• Household cleaning.

Summary

• Strong bases $(NaOH, KOH, Mg(OH)₂, Ca(OH)₂)$fully dissociate in water.
• Weak bases $(Na₂CO₃, CaCO₃, NH₃, NaHCO₃)$ partially dissociate.
• Bases are used in industrial, household, and medical applications.