Waec Biology Past Questions and Answers

Question 1591:

• WAEC 2015

A student used the following steps in testing for a non-reducing sugar.
I. added Benedict's solution to the sugar solution
ll. added dilute hydrochloric acid to the sugar and boiled it;
lll. added sodium hydroxide solution to the solution in ll. and boiled;
IV. added Benedict's solution to the cooled solution in lll.
Use this information above to answer the question.
Why did the student add the dilute hydrochloric acid to the sugar solution in step ll? To

A. Oxidize the sugar solution
B. Hydrolyse the sugar solution
C. Dry the sugar solution
D. Increase the volume of the sugar solution

Question 1592:

• WAEC 2015

A student used the following steps in testing for a non-reducing sugar.
I. added Benedict's solution to the sugar solution
ll. added dilute hydrochloric acid to the sugar and boiled it;
lll. added sodium hydroxide solution to the solution in ll. and boiled;
IV. added Benedict's solution to the cooled solution in lll.
Use this information above to answer the question.
What is the importance of step ll in the testing process? To

A. Neutralize the sugar solution
B. Soften the sugar solution
C. Change the colour of the sugar solution
D. Increase the acid content of the sugar solution

Question 1593:

• WAEC 2015

The colour change to be observed in step IV is

A. Blue-black
B. Brick-red
C. Purple
D. Violet

Question 1594:

• WAEC 2015

Which of the following organs of the alimentary canal is not correctly matched with its function?

A. Gall bladder- stores bile
B. Liver - stores glycogen
C. Appendix - releases enzymes
D. Teeth = grind food

Question 1595:

• WAEC 2015

A person suffering from obstruction of the bile duct is advised not to eat fats and oil because

A. Bile digests fats and oil
B. Fats and oil can only be absorbed whenbile is absent
C. Bile emulsifies fat and oil
D. Bile adds water to digesting food