Question 1

Which of the following must we know when we carry out a titration?
A) the concentrations of all reactants except one
B) the stoichiometric ratio of the reactants
C) the volumes all reactants
D) all of the above

Accepted Answer

We must know the concentrations of all reactants except one in order to perform a titration accurately. Additionally, we need to know the stoichiometric ratio of the reactants and the volumes of all reactants used in the titration. Therefore, all of the above are important pieces of information for a successful titration.

Question 2

Which piece of glassware do we use to deliver a variable but precisely known volume of solution during a titration?
A) a buret
B) an Erlenmeyer flask
C) a graduated cylinder
D) a volumetric pipet

Accepted Answer

A buret is designed for precise measurement and delivery of a variable volume of solution during a titration. It has a stopcock that allows for controlled release of the solution, ensuring accurate measurement. Graduated cylinders and Erlenmeyer flasks are better suited for less precise measurements or mixing solutions, while volumetric pipets are better suited for delivering a fixed volume of solution.

Question 3

Which of the following solutions can function as a buffer? A) a solution containing HCl and NaCl B) a solution containing NaOH and NaCl C) a solution containing NH₃ and NH₄Cl D) none of the above

Accepted Answer

A buffer solution is made from a weak acid and its conjugate base or a weak base and its conjugate acid. NH3 (ammonia) is a weak base and NH4Cl provides the conjugate acid (NH4+), making it a buffer solution.

Question 4

The term "litmus test" is commonly used to mean a totally definitive test. In chemistry litmus is used as an acid-base indicator. Which of the following properly relates the chemical and common usages of the term "litmus test"?
A) Common usage is correct because the litmus test definitively defines a substance as an acid or a base.
B) Common usage is correct because litmus dye changes color at pH = 7.
C) Common usage is incorrect because litmus dye changes color over a range, most of which is above pH = 7.
D) Common usage is incorrect because litmus dye changes color over a range, most of which is below pH = 7.

Accepted Answer

The answer of The term "litmus test" is commonly used...

Question 5

Which of the following solutions can function as a buffer? A) a solution containing HCl and NaCl B) a solution containing NaOH and NaCl C) a solution containing HC₂H₃O₂ and NaC₂H₃O₂ D) all of the above

Accepted Answer

A buffer solution is made from a weak acid and its conjugate base or a weak base and its conjugate acid. HC2H3O2 (acetic acid) and NaC2H3O2 (sodium acetate) form a buffer solution.

Question 6

In a particular titration experiment a 25.0 mL sample of an unknown monoprotic acid required 30.0 mL of 0.200 M NaOH for the end point to be reached. What is the concentration of the acid?
A) 0.120 M
B) 0.167 M
C) 0.240 M
D) 0.333 M

Accepted Answer

The answer of In a particular titration experiment a 25.0...

Question 7

Which of the following solutions will require the most NaOH in a titration experiment? Assume complete neutralization. A) 25 mL of 0.500 M HC₂H₃O₂ B) 25 mL of 0.250 M H₂SO₄ C) 25 mL of 0.167 M H₃PO₄ D) They all require the same amount.

Accepted Answer

Each acid provided has one hydrogen ion (H+) available for neutralization, regardless of the molarity. Since the volume of each solution is the same (25 mL), the amount of NaOH required for complete neutralization will be the same for all solutions, assuming a 1:1 molar ratio of acid to base for neutralization.

Question 8

Which of the following solutions will require the most NaOH in a titration experiment? A) 25 mL of 0.5 M HCl B) 25 mL of 0.5 M HCOOH C) 25 mL of 0.5 M HC₂H₃O₂ D) They all require the same amount.

Accepted Answer

All solutions have the same volume and molarity. NaOH will neutralize them in a 1:1 mole ratio regardless of the acid type, so they all require the same amount of NaOH.

Question 9

Which piece of glassware do we generally use to deliver a predetermined fixed volume of solution in a titration?
A) an Erlenmeyer flask
B) a graduated cylinder
C) a volumetric pipet
D) none of the above

Accepted Answer

A volumetric pipet is designed to deliver a specific volume of solution accurately, making it the best choice for titrations where precise volumes are required. Erlenmeyer flasks and graduated cylinders are not as precise or accurate for this purpose.

Question 10

Which of the following is true of pH?
A) It can be used to determine the chemical identity of an acid.
B) It is a measure of acid concentration.
C) It is a measure of acid strength.
D) It is a measure of the overall acidity.

Accepted Answer

pH is a measure of the overall acidity or alkalinity of a solution, indicating the concentration of hydrogen ions.

Question 11

As student doing a titration of HNO₃ with sodium hydroxide wanted to use Clayton yellow as an indicator. Clayton yellow changes color at pH = 12.7. Which of the following will be true of this experiment? A) The concentration of HNO₃ will be reported as too high. B) The concentration of HNO₃ will be reported as too low. C) The concentration of HNO₃ will be reported correctly. D) The experiment cannot be done at all.

Accepted Answer

The answer of As student doing a titration of HNO₃...

Question 12

In a particular titration experiment a 25.0 mL sample of an unknown monoprotic acid required 30.0 mL of 0.200 M NaOH for the end point to be reached. Which of the following can be determined from the information given here?
A) the identity of the acid sample
B) the pH of the acid sample
C) the strength of the acid sample
D) none of the above

Accepted Answer

The answer of In a particular titration experiment a 25.0...

Question 13

In a particular titration experiment a 25.0 mL sample of an unknown diprotic acid required 30.0 mL of 0.200 M NaOH for the end point to be reached. What is the concentration of the acid?
A) 0.120 M
B) 0.167 M
C) 0.240 M
D) 0.333 M

Accepted Answer

The answer of In a particular titration experiment a 25.0...

Question 14

In a particular titration experiment a 30.0 mL sample of an unknown monoprotic acid required 25.0 mL of 0.200 M NaOH for the end point to be reached. What is the concentration of the acid?
A) 0.120 M
B) 0.167 M
C) 0.240 M
D) 0.333 M

Accepted Answer

The balanced chemical equation for the reaction between the monoprotic acid and NaOH is:

HA + NaOH → NaA + H2O

Here, HA is the monoprotic acid, NaOH is the sodium hydroxide, NaA is the sodium salt of the acid, and H2O is water.

According to the stoichiometry of the equation, 1 mole of NaOH reacts with 1 mole of HA.

Given that the volume of NaOH used is 25.0 mL and the concentration of NaOH is 0.200 M, the number of moles of NaOH used can be calculated as:

moles of NaOH = volume × concentration = 25.0 mL × 0.200 mol/L = 0.00500 moles

Since 1 mole of NaOH is equivalent to 1 mole of HA, the number of moles of HA can be calculated as:

moles of HA = moles of NaOH = 0.00500 moles

Given that the volume of the acid sample is 30.0 mL, the concentration of the acid can be calculated as:

concentration of HA = moles of HA / volume = 0.00500 moles / 30.0 mL = 0.1667 mol/L ≈ 0.167 M

Therefore, the concentration of the unknown monoprotic acid is 0.167 M, which corresponds to choice B.

Question 15

As student doing a titration of HNO₃ with sodium hydroxide wanted to use methyl orange as an indicator. Methyl orange changes color at pH = 3.7. Which of the following will be true of this experiment? A) The concentration of HNO₃ will be reported as too high. B) The concentration of HNO₃ will be reported as too low. C) The concentration of HNO₃ will be reported correctly. D) The experiment cannot be done at all.

Accepted Answer

The answer of As student doing a titration of HNO₃...

Question 16

Which of the following is characteristic of a buffer?
A) The pH will go down significantly when OH- is added to the buffer.
B) The pH will go down very slightly when OH- is added to the buffer.
C) The pH will go up significantly when OH- is added to the buffer.
D) The pH will go up very slightly when OH- is added to the buffer.

Accepted Answer

A buffer resists changes in pH, so when OH- is added, the pH will increase only slightly.

Question 17

Which of the following is characteristic of a buffer? A) The pH will go down significantly when H₃O⁺ is added to the buffer. B) The pH will go down very slightly when H₃O⁺ is added to a buffer. C) The pH will go up significantly when H₃O⁺ is added to the buffer. D) The pH will go up very slightly when H₃O⁺ is added to the buffer.

Accepted Answer

A buffer is a solution that resists changes in pH when small amounts of acid or base are added. Therefore, the pH change should be minimal. Option B states that the pH will go down very slightly, which is characteristic of a buffer. Option A and C state that the pH will go down or up significantly, which is not characteristic of a buffer. Option D states that the pH will go up very slightly, but it is not the best choice because a buffer can resist small amounts of both acid and base, and not just base.

Question 18

The actual reaction in a titration generally is carried out in which of the following pieces of glassware?
A) a buret
B) an Erlenmeyer flask
C) a graduated cylinder
D) none of the above

Accepted Answer

The reaction in a titration is typically carried out in an Erlenmeyer flask, which is a conical flask with a wide mouth and a narrow neck. The buret is used to deliver the titrant, and the graduated cylinder is used to measure the volume of the analyte.

Question 19

Which of the following solutions can function as a buffer? A) a solution containing HCl and NaCl B) a solution containing NaOH and NaCl C) a solution containing H₂SO₄ and NaHSO₄ D) none of the above

Accepted Answer

A buffer solution typically consists of a weak acid and its conjugate base or a weak base and its conjugate acid. None of the given options provide such a combination.

Question 20

Which of the following solutions can function as a buffer? A) a solution containing HC₂H₃O₂ and NaC₂H₃O₂ B) a solution containing H₂CO₃ and NaHCO₃ C) a solution containing NH₃ and NH₄Cl D) all of the above

Accepted Answer

All the solutions listed contain a weak acid and its conjugate base or a weak base and its conjugate acid, which are necessary components for a buffer solution.

Quiz 8: Acids and Bases

Which of the following must we know when we carry out a titration?

Which piece of glassware do we use to deliver a variable but precisely known volume of solution during a titration?

Which of the following solutions can function as a buffer?

The term "litmus test" is commonly used to mean a totally definitive test. In chemistry litmus is used as an acid-base indicator. Which of the following properly relates the chemical and common usages of the term "litmus test"?

Which of the following solutions can function as a buffer?

In a particular titration experiment a 25.0 mL sample of an unknown monoprotic acid required 30.0 mL of 0.200 M NaOH for the end point to be reached. What is the concentration of the acid?

Which of the following solutions will require the most NaOH in a titration experiment? Assume complete neutralization.

Which of the following solutions will require the most NaOH in a titration experiment?

Which piece of glassware do we generally use to deliver a predetermined fixed volume of solution in a titration?

Which of the following is true of pH?

As student doing a titration of HNO3 with sodium hydroxide wanted to use Clayton yellow as an indicator. Clayton yellow changes color at pH = 12.7. Which of the following will be true of this experiment?

In a particular titration experiment a 25.0 mL sample of an unknown monoprotic acid required 30.0 mL of 0.200 M NaOH for the end point to be reached. Which of the following can be determined from the information given here?

In a particular titration experiment a 25.0 mL sample of an unknown diprotic acid required 30.0 mL of 0.200 M NaOH for the end point to be reached. What is the concentration of the acid?

In a particular titration experiment a 30.0 mL sample of an unknown monoprotic acid required 25.0 mL of 0.200 M NaOH for the end point to be reached. What is the concentration of the acid?

As student doing a titration of HNO3 with sodium hydroxide wanted to use methyl orange as an indicator. Methyl orange changes color at pH = 3.7. Which of the following will be true of this experiment?

Which of the following is characteristic of a buffer?

Which of the following is characteristic of a buffer?

The actual reaction in a titration generally is carried out in which of the following pieces of glassware?

Which of the following solutions can function as a buffer?

Which of the following solutions can function as a buffer?

As student doing a titration of HNO₃ with sodium hydroxide wanted to use Clayton yellow as an indicator. Clayton yellow changes color at pH = 12.7. Which of the following will be true of this experiment?

As student doing a titration of HNO₃ with sodium hydroxide wanted to use methyl orange as an indicator. Methyl orange changes color at pH = 3.7. Which of the following will be true of this experiment?