Question 1

Which of the following statements describes an acidic solution?

Accepted Answer

An acidic solution is characterized by having a higher concentration of hydrogen ions ([H+]) than hydroxide ions ([OH-]).

Question 2

Qualitatively, what happens to the hydroxide ion concentration if you decrease the hydronium ion concentration?

Accepted Answer

By decreasing the hydronium ion concentration, the equilibrium shifts to the left in the following reaction: H3O+ + OH- ↔ 2H2O. This means that more hydroxide ions (OH-) will form, causing an increase in their concentration. This increase is not balanced by a decrease in the concentration of hydroxide ions, as suggested in option A. Option B is incorrect because the concentration of hydroxide ions cannot increase while the ratio stays the same, as it would mean that the concentration of hydronium ions also increases. Therefore, option C is the best choice as it accurately describes the situation.

Question 3

Which of the above illustrations shows a neutral aqueous solution?

Accepted Answer

The answer of Which of the above illustrations shows a...

Question 4

What would the concentration of OH^- be if the concentration of H₃O⁺ was 1 × 10^-⁵M? [H₃O⁺] × [OH^-] = K_w= 1 × 10^-14

Accepted Answer

The answer of What would the concentration of OH^- be...

Question 5

Which of the following reactions illustrates an amphoteric compound?

Accepted Answer

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Question 6

What would the concentration of H₃O⁺ be if the concentration of OH^- was 1 × 10^-1M? [H₃O⁺] × [OH^-] = K_w= 1 × 10^-14

Accepted Answer

The answer of What would the concentration of H₃O⁺ be...

Question 7

As the hydronium ion concentration increases, the pH ________.

Accepted Answer

As the hydronium ion concentration increases, the acidity of the solution increases, which in turn decreases the pH value. Therefore, the correct choice is A.

Question 8

What do the brackets in the following equation represent? [H₃O⁺] × [OH^-] = K_w

Accepted Answer

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Question 9

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

Accepted Answer

The hydronium ion concentration in a solution with a pH of 10 is 1 × 10^-10 M. This is because pH is calculated as -log[H3O+], so if pH = 10, then [H3O+] = 10^-10 M.

Question 10

Which of the above illustrations shows an acidic aqueous solution?

Accepted Answer

The answer of Which of the above illustrations shows an...

Question 11

Arrange the following images of an aqueous base solution in order of increasing base strength:

Accepted Answer

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Question 12

What would the concentration of H₃O⁺ be if the concentration of OH^- was 1 × 10^-11M? [H₃O⁺] × [OH^-] = K_w= 1 × 10^-14

Accepted Answer

The concentration of H₃O⁺ can be calculated using the formula [H₃O⁺] × [OH^-] = K_w. Given [OH^-] = 1 × 10^-11M and K_w = 1 × 10^-14, [H₃O⁺] = K_w / [OH^-] = 1 × 10^-14 / 1 × 10^-11 = 1 × 10^-3M.

Question 13

Qualitatively, what happens to the hydronium ion concentration if you increase the hydroxide ion concentration?

Accepted Answer

Increasing the hydroxide ion concentration in a solution will decrease the hydronium ion concentration to maintain the product of their concentrations at a constant value (1.0 x 10^-14 at 25°C), not increase it. None of the provided options accurately describe this relationship.

Question 14

What would the concentration of OH^- be if the concentration of H₃O⁺ was 1 × 10^-8M? [H₃O⁺] × [OH^-] = K_w= 1 × 10^-14

Accepted Answer

Given the ion product of water (Kw) is 1 × 10^-14 M^2, and the concentration of H3O+ is 1 × 10^-8 M, the concentration of OH- can be found by dividing Kw by the concentration of H3O+. Therefore, [OH-] = 1 × 10^-14 M^2 / 1 × 10^-8 M = 1 × 10^-6 M.

Question 15

Which of the above illustrations shows a basic aqueous solution?

Accepted Answer

The answer of Which of the above illustrations shows a...

Question 16

Sodium hydroxide, NaOH, is a strong base, which means that it readily accepts hydrogen ions. What products are formed when sodium hydroxide accepts a hydrogen ion from a water molecule?

Accepted Answer

The answer of Sodium hydroxide, NaOH, is a strong base,...

Question 17

A weak acid is added to a concentrated solution of hydrochloric acid. Does the solution become more or less acidic?

Accepted Answer

When a weak acid is added to a concentrated solution of hydrochloric acid, the acid becomes more dilute. This means there will be a less concentrated solution of hydronium ions, making the solution less acidic. Therefore, the answer is B. There will not be an increase in hydroxide ions since hydrochloric acid is an acid and doesn't produce hydroxide ions.

Question 18

Which of the following solutions is the most acidic?

Accepted Answer

The lower the pH, the more acidic the solution. Option D has a pH of 4, which is the lowest in the given options and therefore the most acidic. Options A and E have a pH of 14, which is the highest possible value on the pH scale and represents a strongly basic solution. Option C has a pH of 7, which is neutral. Option B has a pH of 10, which is basic but not as strongly basic as options A and E.

Question 19

Which of the following statements describes a basic solution?

Accepted Answer

A basic solution is characterized by a higher concentration of hydroxide ions ([OH-]) than hydrogen ions ([H+]), which means [OH-] > [H+].

Question 20

Which of the following statements describes a neutral solution?

Accepted Answer

A neutral solution has an equal concentration of hydrogen ions (H+) and hydroxide ions (OH-), which means the pH of a neutral solution is 7. The ratio of [H+] to [OH-] in a neutral solution is 1:1, which can be represented as [H+]/[OH-] = 1. Using the equation for pH, pH = -log[H+], a pH of 7 means the concentration of H+ is 1 x 10^-7 M. Therefore, the ratio of [H+] to [OH-] in a neutral solution can also be written as 1 x 10^-7 M / 1 x 10^-7 M = 1, which is the same as option E.

Quiz 18: Two Classes of Chemical Reactions