Biochem Module 2 Exam Questions with Correct Answers – 2024/2025 Academic Year

biochem module 2 exam questions and
answers 2024\2025 A+ Grade


The pH of a solution of 0.0010 M NaOH is:



1

11

8

0

14
- correct answer 11 [Kw=[H+ ][OH- ] = 1.0 x 10-14; [H+ ][0.0010] = 1.0 x 10-14 [H+ ]=1.0 x 10-11; pH=-
log[1.0 x 10-11;]=11]



Water is a unique molecule. Which of the following contributes to water's unique place in the chemical
world?



- The geometry of the molecule

- The polarity of the O-H bonds

- The ability of water molecules to hydrogen bond

- The bond angle of water

- All of the answers are correct
- correct answer - All of the answers are correct



The bent shape of water is due to ______________.



- The dipole arrows in a water molecule - - The electronegativity difference between hydrogen and
oxygen

, - The unequal electron sharing between hydrogen and oxygen

- The unshared electron pairs on the oxygen atom

- None of the answers are correct
- correct answer - The unshared electron pairs on the oxygen atom



The H+ concentration of a solution is 1.2 x 10-3 M. What is the pH?



-1.20

1.20

3.12

-2.92

2.92
- correct answer 2.92



If the Ka of an acid is 5.63 x 10-3, what is the pKa?



6.86

2.25

5.63

10.12

1.38
- correct answer 2.25 [pKa = -log(5.63 x 10-3) = 2.25]



List the acids in DECREASING order of strength (strongest to weakest):

Nitrous acid (Ka = 4.0 x 10-4);

acetic acid (Ka = 1.7 x 10-5);

phosphoric acid (Ka = 7.3 x 10-3)



- Nitrous acid, acetic acid, phosphoric acid

- Acetic acid, nitrous acid, phosphoric acid