Chem Chapter 14

What is the pH of a 0.100 M dichloroacetic acid solution? (Ka = 3.32 x 10-2) 1.239 1.363 1.062 1.000 1.12

1.363

What is the pH of a solution prepared by dissolving 0.100 g of NaNH2 in enough water to make 4.50 x 102 mL of solution? 2.244 5.244 8.756 11.756 13.347

11.756

Which OH- concentration and classification (acidic vs. basic) are correctly matched for a solution in which the H3O+ concentration is 2.3 x 10-4 M? 2.3 x 10-18 M : acidic 4.3 x 10-11 M : acidic 4.3 x 10-11 M : basic 2.3 x 10-4 M : acidic 2.3 x 1010 M : acidic

4.3 x 10-11 M : acidic

Which solution is not correctly matched to the pH? 6.5 x 10-6 M NaOH : pH = 5.19 0.0039 M NaOH : pH = 11.59 0.020 M HCl : pH = 1.70 2.3 x 10-4 M HNO3 : pH = 3.64

6.5 x 10-6 M NaOH : pH = 5.19

What is the pH of a 0.10 M NaF solution? (Ka of HF = 3.5 x 10-4) 2.23 5.77 8.23 2.46 11.84

8.23

Which statement concerning an aqueous solution of the weak acid HNO2 is correct? The only species in solution is HNO2. A small amount of H3O+ and NO2- exists in solution. The NO2- is a very weak base. The primary species in a solution of HNO2 are H3O+ and NO2-. In a water solution of HNO2 the amount of H3O+ is much greater than the amount of NO2- in solution.

A small amount of H3O+ and NO2- exists in solution.

In which pair of reactants is the direction of the curved arrow used in Lewis acid-base reactions incorrectly indicated? (The head of the arrow is pointed at the species to which the arrow is drawn.) AlCl3 + NH3: The arrow should be drawn from the Al of AlCl3 to the N of NH3. (CH3)2C=O + H3O+: The arrow should be drawn from the O of (CH3)C=O to the H of H3O+. H3O+ + F-: The arrow should be drawn from the F- ion to the H of H3O+. HCO2H + OH-: The arrow should be drawn from the O of OH to the first H in the formula HCO2H. P(CH3)3 + HI: The arrow should be drawn from the P of PCl3 to the H of HI.

AlCl3 + NH3: The arrow should be drawn from the Al of AlCl3 to the N of NH3.

Which statement concerning the oxoacids is not true? As the electronegativity of the atom Y in the series HOYO increases, the acid strength will increase. As the oxidation number of the atom Y in the series HOYOn increases, the acid strength increases. As the number of oxygen atoms in the series HOYOn decreases, the acid strength increases. As the stability of the anion of an oxoacid increases, the acid strength also increases. As the positive charge on Y in the series HOYOn decreases, the acid strength decreases.

As the number of oxygen atoms in the series HOYOn decreases, the acid strength increases.

Which statement is true? As the strength of a weak acid decreases, the percent dissociation increases. As the strength of a weak acid increases, the percent dissociation decreases. As the value of Ka increases, the percent dissociation increases. As the concentration of a weak acid increases, the percent dissociation increases. The percent dissociation of a weak acid is independent of the identity of the weak acid.

As the value of Ka increases, the percent dissociation increases.

Which compound cannot be a Brønsted-Lowry base? HCl BH3 PH3 H2Se H2O

BH3

Which compound is a Lewis acid only (not Arrhenius or Brønsted-Lowry)? HBr HCN H3BO3 BH3 CH3COOH

BH3

Which is not a formula for a form of the hydronium cation? H9O4+ H6O2+ H7O3+ H3O+ H5O2+

H6O2+

Which reaction does not show the equilibrium reaction that occurs in an aqueous solution of a weak base? H2PO4-(aq) + H2O(l) H3PO4(aq) + OH-(aq) HPO42-(aq) + H2O(l) H2PO4-(aq) + OH-(aq) IO3-(aq) + H2O(l) HIO3(aq) + OH-(aq) CN-(aq) + H2O(l) HCN(aq) + OH-(aq) HAsO42-(aq) + H2O(l) AsO43- + H3O+(aq)

HAsO42-(aq) + H2O(l) AsO43- + H3O+(aq)

Which list gives equal concentrations of the following solutions in order of decreasing acidity? HC3H5O3 (Ka = 1.4 x 10-4) H2O (Ka = 1.0 x 10-14) HOCl (Ka = 3.5 x 10-8) HCN (Ka = 4.9 x 10-10) HCl (Ka = 2 x 106) HCl, HC3H5O3, HOCl, HCN, H2O HCl, HC3H5O3, HOCl, H2O, HCN HCN, HOCl, HCl, HC3H5O3, H2O H2O, HCN, HOCl, HC3H5O3, HCl HC3H5O3, HCl, HOCl, HCN, H2O

HCl, HC3H5O3, HOCl, HCN, H2O

Which reaction does not represent what actually happens when HF dissolves in water? HF(aq) + H2O(l) H3O+(aq) + F-(aq) HF(aq) + 3H2O(l) (H(H2O)3)+ + F-(aq) HF(aq) + 4H2O(l) (H(H2O)4)+ + F-(aq) HF(aq) H+(aq) + F(aq)- HF(aq) + 2H2O(l) (H(H2O)2)+ + F-(aq)

HF(aq) H+(aq) + F(aq)-

Which is not considered a "strong" acid? HNO2 HClO4 H2SO4 HBr HI

HNO2

Which is not an Arrhenius base? N(CH3)3 Ca(OH)2 water Al(OH)4- LiOH

N(CH3)3

Which of these species is a Lewis acid? CN- CH3CH2N2 NO2 OH- F-

NO2

Which statement is true regarding strengths of acids and bases? All weak acids are equally weak. The conjugate of a "weak" acid is a "strong" base. The conjugates of strong acids and strong bases have no significant acid-base properties in aqueous solutions and are essentially "neutral." A weaker acid can be mixed with a weaker base to yield a stronger acid and a stronger base. Once a hydrogen cation dissociates from a weak acid, it never pairs itself again with the conjugate base.

The conjugates of strong acids and strong bases have no significant acid-base properties in aqueous solutions and are essentially "neutral."

he acid-base indicator methyl red is added to a 0.1 M HCl solution. What is the most likely color change that occurs when an excess of a 0.1M NaOH solution is added to the HCl-methyl red solution? (The equilibrium equation for methyl red is HIn(aq)(red) + H2O(l) In-(aq)(yellow) + H3O+(aq).) The solution remains yellow. The solution changes from red to yellow. The solution remains red. The solution changes from yellow to red. The solution remains orange.

The solution changes from red to yellow.

Which salt will form an acidic solution when dissolved in water? KF CaCl2 NaBr LiHS Zn(NO3)2

Zn(NO3)2

What is the [H3O+] and [OH-] of a solution having a pH = 7.34? [H3O+] = 0.87 M and [OH-] = 1.1 x 10-14 M [H3O+] = 4.6 x 10-8 M and [OH-] = 2.2 x 10-7 M [H3O+] = 4.6 x 10-8 M and [OH-] = 4.6 x 10-22 M [H3O+] = 4.57 x 10-8 M and [OH-] = 2.19 x 10-7 M [H3O+] = 0.866 M and [OH-] = 1.16 x 10-14 M

[H3O+] = 4.6 x 10-8 M and [OH-] = 2.2 x 10-7 M

Many anions that form water-soluble salts also form strong acids when paired with hydrogen. Which anion would be an exception to this observation? perchlorate sulfate nitrate chloride acetate

acetate

Which common substance is acidic? baking soda household ammonia coffee human blood milk of magnesia

coffee

For solutions of equal concentration, which acid is the most acidic? boric acid, Ka = 5.8 x 10-10 saccharin, Ka = 2.1 x 10-12 phenol, Ka = 1.3 x 10-10 lactic acid, Ka = 1.4 x 10-4 All of these acids are equally acidic because they are all of equal concentration.

lactic acid, Ka = 1.4 x 10-4

Which indicator would be best for measuring pH values near pH 5? methyl red phenol red alizarin cresol red phenolphthalein

methyl red

Which is not a valid expression for pOH? pOH = pKw-pH pOH = -log(10-(14-pH)) pOH = -log(Kw/[H+]) pOH = -log[OH-] pOH = 14 - log[H+]

pOH = 14 - log[H+]

The third H+ of H3PO4 is much more difficult to remove than the second H+ because the positive charge on the ion that forms when the first two H+ ions are removed holds the proton tighter. the negative charge on the ion that forms when the first two H+ ions are removed holds the proton tighter. the PO43- ion that forms when the third H+ is removed is a strong acid. the PO43+ ion that forms when the third H+ is removed is a relatively strong weak base. the PO43- ion that forms when the third H+ is removed is a relatively strong weak acid.

the negative charge on the ion that forms when the first two H+ ions are removed holds the proton tighter.

All of the H3O+ ions are assumed to come from the weak acid in an aqueous solution because there are no other acids present. water does not contribute any H3O+ to the solution. the value of Kw is very small. any conjugate base that forms reacts with any excess acid. the value of Ka is smaller than the value of Kw.

the value of Kw is very small.