Question 1

Which of the following best describes a buffer solution?

Accepted Answer

A solution that resists changes in pH when moderate amounts of acids or bases are added.

Question 2

In the reaction $$\mathrm{HCl(aq) + NaOH(aq) \rightarrow H_2O(l) + NaCl(aq)}$$, which compound is the salt formed?

Accepted Answer

NaCl

Question 3

A student adds a strong acid to a buffer made of $$\mathrm{NH_3$(aq)}$$ and $$\mathrm{NH_4Cl(aq)}. $$Which reaction occurs to resist the pH change?

Accepted Answer

$$\mathrm{NH_3$(aq) + H^+(aq) \rightarrow NH_4$^+(aq)}$$

Question 4

Which scenario is most likely to result in a reaction that does NOT go to completion?

Accepted Answer

Weak acid + weak base

Question 5

During a titration, what is the primary purpose of using an indicator?

Accepted Answer

To determine the exact point at which the acid and base have completely reacted.

Question 6

Which of the following best explains why blood acts as a buffer?

Accepted Answer

Blood contains weak acids and their salts, allowing it to resist changes in pH.

Question 7

If you titrate $$\mathrm{HC_2H_3O_2(aq)} ($$acetic acid) with $$\mathrm{NaOH(aq)}$$, which of the following is true about the reaction?

Accepted Answer

The reaction will go to completion, even though acetic acid is a weak acid.

Question 8

Which equation represents the reaction when a strong base is added to a buffer made of $$\mathrm{HC_2H_3O_2(aq)}$$ and $$\mathrm{NaC_2H_3O_2(aq)}$$?

Accepted Answer

$$\mathrm{HC_2H_3O_2(aq) + OH^-(aq) \rightarrow C_2H_3O_2^-(aq) + H_2O(l)}$$

Question 9

Which of the following statements about indicators is correct?

Accepted Answer

Indicators are acids or bases that change color as they gain or lose hydrogen atoms.

Question 10

A titration is performed using $$\mathrm{HCl}$$ and $$\mathrm{NaOH}. If 25.0 mL of$$ $$\mathrm{0.100\;M\;NaOH} is $$required to neutralize 50.0 mL of $$\mathrm{HCl}$$, what is the molarity of the $$\mathrm{HCl}$$ solution?

Accepted Answer

$$0.050\;M$$

Question 11

Which of the following is NOT a characteristic of a strong acid-base reaction?

Accepted Answer

The reaction is reversible and does not go to completion.

Question 12

What is the main reason that a weak acid and a weak base reaction is uncommon?

Accepted Answer

Neither has a strong desire to transfer an $$\mathrm{H^+}$$ ion.

Question 13

Which of the following best describes the process of titration?

Accepted Answer

Controlled addition and measurement of a solution of known concentration to react completely with a measured amount of a solution with unknown concentration.

Question 14

Which of the following is a real-world example of a buffer system?

Accepted Answer

Blood

Question 15

If phenol red is yellow at pH 7 and turns red at pH 8, what can you infer about its use as an indicator?

Accepted Answer

It is useful for detecting changes in pH near neutral.

Question 16

Which of the following equations represents the neutralization reaction between $$\mathrm{HBr}$$ and $$\mathrm{Al(OH)_3}$$?

Accepted Answer

$$\mathrm{3HBr(aq) + Al(OH)_3(s) \rightarrow $$AlBr_3$$(aq) + 3H_2O(l)}$$

Question 17

Which of the following is true about the universal indicator?

Accepted Answer

It covers nearly the entire pH scale.

Question 18

A buffer is made from $$\mathrm{HC_2H_3O_2}$$ and $$\mathrm{NaC_2H_3O_2}. $$What happens when a strong acid is added?

Accepted Answer

$$\mathrm{C_2H_3O_2^-(aq) + H^+(aq) \rightarrow HC_2H_3O_2(aq)}$$

Question 19

Which of the following best describes a salt in the context of acid-base reactions?

Accepted Answer

A compound made from the cation of a base and the anion of an acid.

Acid-Base Reactions, Buffers, Indicators, and Titrations

Guida di studio - Domande di pratica

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