Q: Which of the following is a correct representation of the relationship between $[\mathrm{H^+}]$ and $[\mathrm{OH^-}]$ in any aqueous solution at $25^\circ$C?

$[\mathrm{H^+}] \times [\mathrm{OH^-}] = 10^{-14}$

Question 1

Which of the following best explains why changes in pH can drastically affect proteins and other complex molecules in cells?

Accepted Answer

pH changes modify the concentration of $\mathrm{H^+}$ and $\mathrm{OH^-}$ ions, which can disrupt hydrogen bonding and ionic interactions in biomolecules.

Question 2

A solution has a $[\mathrm{H^+}]$ of $10^{-4}$ M. What is the pH of this solution?

Accepted Answer

$4$

Question 3

Which of the following statements about the dissociation of water is correct?

Accepted Answer

A hydrogen atom in a hydrogen bond can shift from one water molecule to another, forming $\mathrm{H_3O^+}$ and $\mathrm{OH^-}$ ions.

Question 4

If the pH of a solution decreases from 6 to 3, how does the $[\mathrm{H^+}]$ concentration change?

Accepted Answer

It increases by 1000 times.

Question 5

Which of the following is a correct representation of the relationship between $[\mathrm{H^+}]$ and $[\mathrm{OH^-}]$ in any aqueous solution at $25^\circ$C?

Accepted Answer

$[\mathrm{H^+}] 	imes [\mathrm{OH^-}] = 10^{-14}$

Question 6

A patient’s blood pH drops to 7.0. What is the most likely consequence?

Accepted Answer

The patient may not survive, as blood pH must remain close to 7.4 for proper cellular function.

Question 7

Which of the following best describes the function of a buffer in biological systems?

Accepted Answer

Buffers maintain stable pH by accepting $\mathrm{H^+}$ when in excess and donating $\mathrm{H^+}$ when depleted.

Question 8

Which of the following is an example of a buffer system in human blood?

Accepted Answer

Carbonic acid-bicarbonate system ($\mathrm{H_2CO_3}$ and $\mathrm{HCO_3^-}$)

Question 9

A solution has a pH of 10. What is the $[\mathrm{OH^-}]$ concentration in this solution?

Accepted Answer

$10^{-4}$ M

Question 10

Which of the following substances acts as a base in aqueous solution?

Accepted Answer

$\mathrm{NaOH}$, because it increases $[\mathrm{OH^-}]$ by dissociation.

Question 11

Which of the following best describes the relationship between pH and $[\mathrm{H^+}]$ concentration?

Accepted Answer

As pH decreases, $[\mathrm{H^+}]$ increases.

Question 12

If enough base is added to a solution to increase $[\mathrm{OH^-}]$ to $10^{-2}$ M, what is the $[\mathrm{H^+}]$ of the solution?

Accepted Answer

$10^{-12}$ M

Question 13

Which of the following is true about hydrophilic and hydrophobic substances?

Accepted Answer

Hydrophilic substances interact with water and dissolve easily, while hydrophobic substances do not.

Question 14

Which property of water allows ice to float on liquid water?

Accepted Answer

Ice has a lower density than liquid water due to hydrogen bonding.

Question 15

A solution has a pH of 2. Compared to a solution with pH 5, how much greater is its $[\mathrm{H^+}]$ concentration?

Accepted Answer

1000 times greater

Question 16

Which of the following is NOT an emergent property of water?

Accepted Answer

Ability to conduct electricity

Question 17

Which equation correctly defines pH?

Accepted Answer

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

Question 18

Which of the following best describes the role of carbonic acid ($\mathrm{H_2CO_3}$) in blood?

Accepted Answer

It acts as a buffer, helping to maintain blood pH by reversible dissociation.

Question 19

Which of the following would result if a solution’s $[\mathrm{H^+}]$ is $10^{-8}$ M?

Accepted Answer

The solution is basic.

Chapter 3 Notes Part B (Acidic and Basic Conditions Affecting Living Organisms: Water Dissociation, Acids, Bases, pH, and Buffers)

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