Hard and soft water - Jamb Chemistry Past Questions and Answers

Question 6:

• JAMB 1997

The synthetic detergents are preferred to soap for laundry using hard water because?

A. Detergents are water soluble while soap is not
B. The calcium salts of detergents are water soluble
C. The magnesium salt of soap is soluble in hard water
D. Soap does not have a hydrocarbon terminal chain

Question 7:

• JAMB 1999

The method that can be used to convert hard water to soft water is

A. Chlorination
B. Passage over activated charcoal
C. The use of an ion-exchange resin
D. Aeration

Question 8:

• JAMB 2000

A side effect of soft water is that

A. It gives offensive taste
B. Excess calcium is precipitated
C. It attcaks lead contained in pipes
D. It encourages the growth of bacteria

Question 9:

• JAMB 2007

When temporary hard water is boiled for sometime in a kettle, the inner surface of the kettle becomes coated with a deposit of

A. Calcium tetraoxosulphate(VI)
B. Calcium trioxocarbonate (IV)
C. Calcium hydrogentrioxocarbonate (IV)
D. Aluminium trioxocarbonate (IV)

Question 10:

• JAMB 2010

Permanent hardness of water can be removed by

A. Filtration
B. Adding slaked lime
C. Adding caustic soda
D. Boiling