Question 1

If the pH of a solution is 10, what is the hydronium ion concentration?

Accepted Answer

The pH scale is inversely related to the concentration of hydronium ions in a solution. A pH of 10 means the hydronium ion concentration is 1 × 10^-10 M.

Question 2

When the hydronium ion concentration equals 10 moles per liter, what is the pH of the solution? Is the solution acidic or basic?

Accepted Answer

The answer of When the hydronium ion concentration equals 10...

Question 3

If the pH of a solution was 7 and you were to increase the hydroxide ion concentration 100x, what would the pH be?

Accepted Answer

Since the pH of the solution is 7, the concentration of hydrogen ions (H+) is equal to the concentration of hydroxide ions (OH-). If we increase the hydroxide ion concentration 100x, then the concentration of hydroxide ions would be 100 times greater than the concentration of hydrogen ions. This means that the concentration of hydrogen ions would become 1/100th of the original concentration. Using the pH formula, we can calculate the new pH:
pH = -log[H+]
pH = -log(1/100[H+])
pH = -(-2 + log[H+])
pH = 2 - log[H+]
Since the pH is decreasing, the solution is becoming more basic. Choice A is the only option that represents a basic pH, so the answer is A.

Question 4

If the pH of a solution is 10, what is the hydroxide ion concentration?

Accepted Answer

The pH scale is defined as the negative logarithm of the hydrogen ion concentration. Therefore, to determine the hydroxide ion concentration, we need to use the relationship that Kw = [H+][OH-] = 1 × 10^-14 at 25°C. Since the pH of the solution is 10, we can calculate the hydrogen ion concentration as follows:

pH = -log[H+]
10 = -log[H+]
[H+] = 10^-10 M

Using Kw = [H+][OH-], we can solve for the hydroxide ion concentration:

1 × 10^-14 = (10^-10) [OH-]
[OH-] = 1 × 10^-4 M

Therefore, the hydroxide ion concentration in the solution is 1 × 10^-4 M, and the best choice is A.

Question 5

Why do we use the pH scale to indicate the acidity of a solution rather than simply stating the concentration of hydronium ions?

Accepted Answer

The pH scale is used because it provides a more convenient way to express the acidity of a solution, given that the concentration of hydronium ions in most solutions is very small and would otherwise involve the use of negative exponents or very small numbers.

Question 6

If you had a 1 M solution of a weak base what would be its pH?

Accepted Answer

A 1 M solution of a weak base would have a pH greater than 7, since weak bases partially dissociate in water to form hydroxide ions (OH-), which increases the pH. A stronger base would have a higher pH, but since this is a weak base, the pH will be closer to neutral (pH 7) but still slightly basic. Therefore, the best choice is D, pH 8.

Question 7

Which of the following solutions is the most acidic?

Accepted Answer

The lower the pH value, the more acidic the solution. A pH of 4 is lower than a pH of 7 or 10, and much lower than a pH of 14. Therefore, option D, a solution with a pH of 4, is the most acidic.

Question 8

If you had a 1 M solution of a weak acid what would be its pH?

Accepted Answer

Weak acids partially dissociate in solution, resulting in a pH less than 7 but significantly higher than 1, making option B (pH 6) the most reasonable choice given the options.

Question 9

What happens to the pH of an acidic solution as water is added?

Accepted Answer

As water is added to an acidic solution, the concentration of hydronium ions decreases and the solution becomes more dilute. This causes the pH to increase, since the pH of an acidic solution is inversely proportional to the concentration of hydronium ions.

Question 10

What does the value of  say about the extent to which water molecule react with themselves?

Accepted Answer

The value of 11ea82ef_47bd_ff5c_aa40_510d137e43c4_TB6000_11 is the autoionization constant of water, also known as Kw. A low value of Kw indicates that water molecules do not react with themselves to form H+ and OH- ions very much, meaning that the extent to which water ionizes is quite small. Therefore, option B is the best choice. Option A is incorrect because a small value of Kw indicates a small extent of ionization, not the other way around. Option C is incorrect because water ionization can be affected by factors such as temperature and pressure. Option D is incorrect because adding an acid to water will change the ion concentration of the solution, but it will not necessarily change the value of Kw.

Question 11

If you had a 1 M solution of a strong base what would be its pH?

Accepted Answer

A strong base has a high concentration of hydroxide ions (OH-) which will increase the pH of a solution. A pH of 14 is the most basic and corresponds to a hydroxide ion concentration of 1 M. Therefore, a 1 M solution of a strong base would have a pH of 13.

Question 12

As the pH increases, the hydroxide ion concentration ________.

Accepted Answer

As the pH increases, it indicates a decrease in the concentration of hydrogen ions (H+) and an increase in the concentration of hydroxide ions (OH-), making the solution more basic.

Question 13

The amphoteric reaction between two water molecules is endothermic, which means that this reaction requires the input of energy in order to proceed: Energy +  O +  O →   + O  The warmer the temperature of the water, the more thermal energy is available for this reaction, and the more hydronium and hydroxide ions are formed. Based on this information, should the value of  be expected to increase, decrease, or stay the same with increasing temperature?

Accepted Answer

The amphoteric reaction between water molecules is endothermic, which means that it requires energy input to proceed. The warmer the temperature of the water, the more thermal energy is available for this reaction, leading to the formation of more hydronium and hydroxide ions. Therefore, the value of 11ea82ef_47be_7498_aa40_c52ee6cca15f_TB6000_11 is expected to increase with increasing temperature. Choices A, B, and D are incorrect based on this information.

Question 14

Pour vinegar onto beach sand from the Caribbean and the result is a lot of froth and bubbles. Pour vinegar onto beach sand from California, however, and nothing happens. Why?

Accepted Answer

Beach sand from the Caribbean and many other tropical climates is made primarily of the calcium carbonate remains of coral and shelled creatures. Vinegar is an acid and the calcium carbonate is a base. Therefore, when vinegar is poured onto Caribbean beach sand, a neutralization reaction occurs and produces carbon dioxide gas, which forms froth and bubbles. In contrast, California beach sand does not contain high amounts of calcium carbonate, so there is no neutralization reaction when vinegar is poured onto it, and no froth or bubbles are produced.

Question 15

Which of the following solutions is the most acidic?

Accepted Answer

A pH of 7 is neutral, and any value below 7 is considered acidic. Since options A, B, and D have pH values above 7, they are basic, not acidic. Therefore, option C, with a pH of 7, is the closest to being acidic, making it the most acidic option among those listed.

Question 16

If the pH of a solution was 7 and you were to increase the hydronium ion concentration 1000x, what would the pH be?

Accepted Answer

The pH scale is logarithmic, meaning that each whole number change represents a tenfold change in hydronium ion concentration. Increasing the hydronium ion concentration by 1000 times (or 10^3 times) would decrease the pH by 3 units, from 7 to 4.

Question 17

If you had a 1 M solution of a strong acid what would be its pH?

Accepted Answer

A strong acid completely dissociates in water, resulting in the solution having a high concentration of H+ ions. Since pH is defined as the negative logarithm of the H+ ion concentration, a 1 M solution of a strong acid would have a pH of 1.

Question 18

When the hydronium ion concentration equals 1 mole per liter, what is the pH of the solution? Is the solution acidic or basic?

Accepted Answer

The pH is calculated as the negative logarithm of the hydronium ion concentration. For a concentration of 1 mole per liter, pH = -log(1) = 0. Since pH < 7, the solution is acidic.

Question 19

Along with the pH scale, there is the pOH scale, which indicates the level of "basicity" in a solution. Accordingly, pOH = -log[OH^-]. What is the sum of the pH and the pOH of a solution always equal to?

Accepted Answer

The answer of Along with the pH scale, there is...

Question 20

What would be the concentration of hydronium ions in a solution that had a pH = -3? Why would such a solution be impossible to prepare?

Accepted Answer

The answer of What would be the concentration of hydronium...

Quiz 10: Acids and Bases in Our Environment

If the pH of a solution is 10, what is the hydronium ion concentration?

When the hydronium ion concentration equals 10 moles per liter, what is the pH of the solution? Is the solution acidic or basic?

If the pH of a solution was 7 and you were to increase the hydroxide ion concentration 100x, what would the pH be?

If the pH of a solution is 10, what is the hydroxide ion concentration?

Why do we use the pH scale to indicate the acidity of a solution rather than simply stating the concentration of hydronium ions?

If you had a 1 M solution of a weak base what would be its pH?

Which of the following solutions is the most acidic?

If you had a 1 M solution of a weak acid what would be its pH?

What happens to the pH of an acidic solution as water is added?

What does the value of say about the extent to which water molecule react with themselves?

If you had a 1 M solution of a strong base what would be its pH?

As the pH increases, the hydroxide ion concentration ________.

Pour vinegar onto beach sand from the Caribbean and the result is a lot of froth and bubbles. Pour vinegar onto beach sand from California, however, and nothing happens. Why?

Which of the following solutions is the most acidic?

If the pH of a solution was 7 and you were to increase the hydronium ion concentration 1000x, what would the pH be?

If you had a 1 M solution of a strong acid what would be its pH?

When the hydronium ion concentration equals 1 mole per liter, what is the pH of the solution? Is the solution acidic or basic?

Along with the pH scale, there is the pOH scale, which indicates the level of "basicity" in a solution. Accordingly, pOH = -log[OH-]. What is the sum of the pH and the pOH of a solution always equal to?

What would be the concentration of hydronium ions in a solution that had a pH = -3? Why would such a solution be impossible to prepare?

Along with the pH scale, there is the pOH scale, which indicates the level of "basicity" in a solution. Accordingly, pOH = -log[OH^-]. What is the sum of the pH and the pOH of a solution always equal to?