$$[\mathrm{H}^+] = 1 \times 10$$^{-4}$$~\mathrm{M}$$

Question 1

Which of the following best describes the pH scale?

Accepted Answer

A negative logarithmic scale measuring the concentration of H$$^+$$ ions.

Question 2

If the concentration of H$$^+$$ ions in a solution increases, what happens to the pH?

Accepted Answer

The pH decreases.

Question 3

A solution has a pH of 7. What does this indicate about the concentrations of H$$^+$$ and OH$$^-$$ ions?

Accepted Answer

The concentration of H$$^+$$ ions equals the concentration of OH$$^-$$ ions.

Question 4

Which equation correctly represents the relationship between pH and hydrogen ion concentration?

Accepted Answer

$$\mathrm{pH} = -\log_{10}[\mathrm{H}^+]$$

Question 5

Which of the following best describes an acid in terms of proton transfer?

Accepted Answer

An acid is a proton donor.

Question 6

What is the effect of a base on the concentration of H$$^+$$ ions in a solution?

Accepted Answer

It decreases the concentration of H$$^+$$ ions.

Question 7

Why do changes in pH have a dramatic effect on living organisms?

Accepted Answer

They alter the shape of molecules, affecting biological function.

Question 8

Which chemical reaction is responsible for ocean acidification as a result of increased atmospheric CO$$_2$$?

Accepted Answer

$$\mathrm{CO}_2 + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{H}_2\mathrm{CO}_3$$

Question 9

Which of the following is a buffer system in the human body that helps maintain pH?

Accepted Answer

Blood

Question 10

A patient is experiencing acidosis. Which of the following is most likely occurring in their blood?

Accepted Answer

The concentration of H$$^+$$ ions is higher than normal.

Question 11

Which of the following is true about buffers in biological fluids?

Accepted Answer

Buffers minimize changes in pH by accepting or donating H$$^+$$ ions.

Question 12

If a solution has a pH of 4, what is the concentration of H$$^+$$ ions?

Accepted Answer

$$[\mathrm{H}^+] = 1 	imes 10$$^{-4}$$~\mathrm{M}$$

Question 13

Which of the following fluids is NOT typically buffered in the human body?

Accepted Answer

Urine

Question 14

What is the role of OH$$^-$$ ions in determining the pH of a solution?

Accepted Answer

Increasing OH$$^-$$ ions increases pH.

Question 15

Which of the following best describes a base?

Accepted Answer

A base is a proton acceptor.

Question 16

A scientist adds a strong acid to a buffered solution. What is the expected outcome?

Accepted Answer

The buffer will minimize the change in pH.

Question 17

Which of the following is a real-world consequence of decreased ocean pH due to acidification?

Accepted Answer

Coral bleaching and death of marine organisms.

Question 18

Which of the following statements about acids and bases is correct?

Accepted Answer

Acids increase H$$^+$$ concentration in solution.

Question 19

A solution has $$[\mathrm{H}^+] = 1 	imes 10$$^{-9}$$~\mathrm{M}. $$What is its pH?

Accepted Answer

$$\mathrm{pH} = 9$$

UNIT 1: pH, Acids, Bases, and Buffers in Biology

Study Guide - Practice Questions