Question 1

Which of the above images represents a solution of the strongest acid (HA)?

Accepted Answer

A) A 
B) B 
C) C 
D) All of the above are strong acids. 
E) None of the above are strong acids.

Question 2

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

Accepted Answer

A) 1 × 10-14 
B) 1 × 10-6 
C) 1 × 108 
D) 1 × 106 
E) 1 × 10-8

Question 3

Which is the stronger acid: H-F or H-I?

Accepted Answer

A) H-F, because the electronegativity of fluorine is higher than that of iodine making the H-F bond more polar and more likely to release the hydrogen ion to solution. 
B) H-F, because acid strength for binary acids decreases "down the group" of the periodic table. 
C) H-I, because iodine releases the hydrogen in order to form  (s)at room temperature. 
D) H-I, because the H-I bond is weaker and so it is easier to break to form hydrogen ions.

Question 4

For the following acid-base reaction, identify which salt is formed. HCl + NaOH ⇌ ???? + H2O

Accepted Answer

A) NaCl 
B) H3OCl 
C) NaOH2 
D) NaOH2Cl 
E) none of the above

Question 5

If you were to increase the pH of rain water the concentration of dissolved CO2 would ________.

Accepted Answer

A) increase because the acid form is neutralized 
B) decrease because you are adding acid 
C) decrease because the acid form is neutralized 
D) increase because you are adding acid

Question 6

Adding more carbon dioxide to the atmosphere causes the concentration of carbonates in the ocean to ________.

Accepted Answer

A) increase 
B) decrease 
C) stay the same because of a negative feedback mechanism 
D) stay the same because of a positive feedback mechanism

Question 7

If the rate at which we produce CO2 were to stop rising, the levels of CO2 in the atmosphere would ________.

Accepted Answer

A) eventually level off 
B) continue to rise 
C) decrease as CO2 is absorbed by plants, soils, and the oceans 
D) This cannot be reasonably predicted

Question 8

For the following reaction, identify whether the compound in bold is behaving as an acid or a base. H3PO4 + H2O ⇌ H2PO4- + H3O+

Accepted Answer

A) acid 
B) base 
C) neither 
D) both 
E) none of the above

Question 9

Sodium bicarbonate, NaHC  , is the active ingredient of baking soda. Compare its structure carefully with the weak acids and bases presented in this chapter and explain how this compound by itself in solution (with no other components)moderates changes in pH.

Accepted Answer

A) Sodium bicarbonate is like two buffer components combined into one molecule, the hydrogen end of the molecule is similar to a weak base, and the sodium end is like a weak acid. 
B) Sodium bicarbonate is like two buffer components combined into one molecule, the hydrogen end of the molecule is similar to a weak acid, and the sodium end is like a weak base. 
C) Sodium bicarbonate is like a buffer, the hydrogen end of the molecule is similar to a weak base. 
D) Sodium bicarbonate is like a buffer, the sodium end of the molecule is like a weak acid.

Question 10

Hydrogen chloride is added to a buffer solution of ammonia, N  , and ammonium chloride, N  ⁺Cl⁻. What is the effect on the concentration of ammonia? What is the effect on the concentration of ammonium chloride?

Accepted Answer

A) HCl reacts with both the ammonia and ammonium chloride, so the concentration of both decreases. 
B) HCl reacts with only the ammonium chloride, so the concentration of the ammonium chloride decreases and the concentration of ammonia increases. 
C) HCl reacts with both the ammonia and ammonium chloride, so the concentration of both increases. 
D) HCl reacts with only the ammonia, so the concentration of the ammonium chloride increases and the concentration of ammonia decreases.

Question 11

What best describes what happens when an acid such as HCl is mixed with water?

Accepted Answer

A) The proton chemically bonded to the chlorine is transferred to a water molecule and forms a chloride ion and a hydronium ion. 
B) A proton from the chlorine nucleus is ejected and captured by a water molecule to form a negatively charged HCl and a new hydronium ion. 
C) A hydroxide ion from the water is transferred to the HCl molecule to form a proton and hydronium ion. 
D) HCl is not an acid. 
E) none of the above

Question 12

In behaving as both an acid and a base, water reacts with itself to form ________.

Accepted Answer

A) hydronium ions, H3O+. 
B) hydroxide ions, OH-. 
C) more water molecules. 
D) two of the above. 
E) all of the above.

Question 13

The main component of bleach is sodium hypochlorite, NaOCl, which consists of sodium ions, Na⁺, and hypochlorite ions,  What products are formed when this compound is reacted with the hydrochloric acid, HCl, of toilet bowl cleaner?

Accepted Answer

A) The products are NaCl,  , and  . 
B) The products are NaOH,  O, and  
C) The products are NaCl and HOCl. 
D) The products are NaOH,  , and

Question 14

How does a base like NH3 raise the hydroxide ion concentration?

Accepted Answer

A) The NH3 molecule removes a proton from a water molecule. 
B) The NH3 molecule releases a proton that has to be neutralized by a water molecule. 
C) The NH3 molecule is not a base and therefore does not change the hydroxide ion concentration. 
D) The NH3 molecule releases reacts with a hydronium molecule, altering the number of hydroxide ions in the process. 
E) none of the above

Question 15

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

Accepted Answer

A) 1 
B) 6 
C) 7 
D) 8 
E) 13

Question 16

Does the hydride ion, H⁻, tend to behave as an acid or a base?

Accepted Answer

A) Hydride ion is unstable and re-reacts with water to form an acid in the form of the hydronium ion, H3O⁺. 
B) Hydride ion has a pair of electrons and acts like a Lewis base since it has a strong tendency to lend or donate that electron pair. 
C) Although the hydride ion has two electrons, they do not pair together. Thus, the hydride ion is incapable of acting as a Lewis base and therefore tends to behave as an acid. 
D) Hydride ion's makeup consists of one proton and two electrons. As such, its tendency is to form neutral hydrogen gas,  , and therefore is neither acidic nor basic, but neutral.

Question 17

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

A) the negative of the product of the hydronium and hydroxide ions 
B) the negative log of  , which is 14 
C) The sum would equal 7, since that would be neutral for pH and pOH. 
D) It is not constant because it depends on the acid/base solution in question.

Question 18

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

Accepted Answer

A) The pH is not influenced by the addition of water. 
B) The pH will decrease as the solution becomes more dilute. 
C) The pH will increase as the solution becomes more dilute. 
D) The pH will decrease since more hydronium ions are produced from the water.

Question 19

According to the following reaction, which molecule is acting as a base? H3O+ + HSO4- → H2O + H2SO4

Accepted Answer

A) H2SO4 
B) H2O 
C) H3O+ 
D) HSO4- 
E) none of the above

Question 20

What happens to the pH of a 1M solution of hydrochloric acid, HCl, as carbon dioxide gas is bubbled into it?

Accepted Answer

A) The pH decreases as the solution becomes more acidic since carbon dioxide reacts to form carbonic acid thus increasing the overall acid concentration. 
B) The pH increases as the solution becomes more basic since the carbon dioxide continues to tie up more and more of the hydrogen ions as associated carbonic acid molecules. 
C) The pH remains unchanged. Carbon dioxide is unable to affect the pH in the presence of such a concentrated solution of such a strong acid. 
D) At first the pH will increase as carbon dioxide ties up the hydrogen ions from the solution. Once the concentration of the resulting carbonic acid becomes greater than 1M, the pH will begin to decrease indicating the presence of more acid.

Exam 10: Acids and Bases in Our Environment

Which of the above images represents a solution of the strongest acid (HA) ?

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

Which is the stronger acid: H-F or H-I?

For the following acid-base reaction, identify which salt is formed. HCl + NaOH ⇌ ???? + H₂O

If you were to increase the pH of rain water the concentration of dissolved CO₂would ________.

Adding more carbon dioxide to the atmosphere causes the concentration of carbonates in the ocean to ________.

If the rate at which we produce CO₂ were to stop rising, the levels of CO₂ in the atmosphere would ________.

For the following reaction, identify whether the compound in bold is behaving as an acid or a base. H₃PO₄ + H₂O ⇌ H₂PO₄^- + H₃O⁺

Sodium bicarbonate, NaHC , is the active ingredient of baking soda. Compare its structure carefully with the weak acids and bases presented in this chapter and explain how this compound by itself in solution (with no other components) moderates changes in pH.

Hydrogen chloride is added to a buffer solution of ammonia, N , and ammonium chloride, N ⁺Cl⁻. What is the effect on the concentration of ammonia? What is the effect on the concentration of ammonium chloride?

What best describes what happens when an acid such as HCl is mixed with water?

In behaving as both an acid and a base, water reacts with itself to form ________.

The main component of bleach is sodium hypochlorite, NaOCl, which consists of sodium ions, Na⁺, and hypochlorite ions, What products are formed when this compound is reacted with the hydrochloric acid, HCl, of toilet bowl cleaner?

How does a base like NH₃ raise the hydroxide ion concentration?

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

Does the hydride ion, H⁻, tend to behave as an acid or a base?

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

According to the following reaction, which molecule is acting as a base? H₃O⁺ + HSO₄^- → H₂O + H₂SO₄

What happens to the pH of a 1M solution of hydrochloric acid, HCl, as carbon dioxide gas is bubbled into it?