Understanding Hard and Soft Water

What are the primary metallic cations responsible for water hardness?

• Iron and zinc

• Copper and lead

• Calcium and magnesium

• Sodium and potassium

How can temporary hardness in water be removed?

• By adding vinegar

• By boiling the water

• By adding chlorine

• By using a water filter

What causes permanent hardness in water?

• Chlorides and nitrates

• Carbonates and bicarbonates

• Sulfates, silicates, and phosphates

• Organic matter

What is the role of sodium carbonate in water softening?

• It acts as a disinfectant

• It increases the water's pH

• It removes calcium ions as calcium carbonate

• It adds calcium ions to the water

What must be done when an ion exchange resin becomes saturated with calcium ions?

• Add more calcium ions

• Wash it with a sodium chloride solution

• Boil the resin

• Replace the resin with a new one