Hard Water and soft water

Soft Water _________________ with soap.

• does not lather

• runs

• covers

• lathers

Hardness in water is caused by the presence of:

• 1. chlorides and sulphates of calcium and magnesium
• 1. carbonates and bicarbonates of zinc and iron
• 1. chlorides and sulphates of aluminium
• 1. carbonates and chlorides of sodium

Boilinng is used to remove ---------------- hardness.

• Permanent

• temporary

Soft water ------------------------ contain salt of calcium and magnesium

• does

• does not

What is water hardness?

• It refers to the level of minerals in the water

• It refers to how frozen water is

• It refers to how deep in the ground the water source is

• It refers to how healthy water is

Hardness in water is caused by the presence of:

• Sodium chloride

• Sodium carbonate

• Calcium chloride

• Potassium nitrate

Permanent hardness in water is caused by the presence of:

• Calcium bicarbonate

• Magnesium sulphate

• Both of them

• None of them

Water is hard when it contains:

• Acid solution

• Precipitate in suspension

• Dissolved sodium salts

• Dissolved Ca and Mg salts

What unwanted material can hard water produce in heating appliances, e.g. kettles and irons?

• Scum

• Scale

• Scurry

• Soap

Soft water does not contain the dissolved substances that hard water does. It is possible to soften hard water by removing the offending ions. Pick the two methods for softening water.

• Using baking soda and using an ion-exchange column

• Using water soda and using an element-exchange column

• Using washing soda and using an ion-exchange column

• Using washing powder and using an ion-exchange column

• Both 3 and 4