According to the Brønsted-Lowry theory, how does each species act in the equilibrium below?

\[{\text{C}}{{\text{H}}_3}{\text{COOH}} + {{\text{H}}_2}{\text{S}}{{\text{O}}_4} \rightleftharpoons {\text{C}}{{\text{H}}_3}{\text{COOH}}_2^ +  + {\text{HSO}}_4^ - \]

D

B

What is the pH of 1.0 × 10⁻³ mol dm⁻³ sodium hydroxide, NaOH(aq)?

K_w = 1.0 × 10⁻¹⁴

A.     3

B.     4

C.     10

D.     11

D

Which solutions have a pH less than 7?

I.     \({\text{N}}{{\text{a}}_2}{\text{C}}{{\text{O}}_3}({\text{aq)}}\)

II.     \({\text{[Fe(}}{{\text{H}}_2}{\text{O}}{{\text{)}}_6}{\text{]C}}{{\text{l}}_3}{\text{(aq)}}\)

III.     \({{\text{(N}}{{\text{H}}_4}{\text{)}}_2}{\text{S}}{{\text{O}}_4}{\text{(aq)}}\)

A.     I and II only

B.     I and III only

C.     II and III only

D.     I, II and III

C

What is the correct expression for the ionic product constant of water, \({K_{\text{w}}}\)?

A.     \({K_{\text{W}}} = \frac{{{\text{[}}{{\text{H}}^ + }{\text{]}}}}{{{\text{[O}}{{\text{H}}^ - }{\text{]}}}}\)

B.     \({K_{\text{W}}}{\text{ = }}\frac{{{\text{[}}{{\text{H}}_2}{\text{O]}}}}{{{\text{[}}{{\text{H}}^ + }{\text{][O}}{{\text{H}}^ - }{\text{]}}}}\)

C.     \({K_{\text{W}}} = {\text{[}}{{\text{H}}^ + }{\text{]}} + {\text{[O}}{{\text{H}}^ - }{\text{]}}\)

D.     \({K_{\text{W}}} = {\text{[}}{{\text{H}}^ + }{\text{][O}}{{\text{H}}^ - }{\text{]}}\)

D

Which of the following is an example of a Lewis acid–base reaction, but not a Brønsted–Lowry acid–base reaction?

A.     \({\text{2CrO}}_4^{2 - }{\text{(aq)}} + {\text{2}}{{\text{H}}^ + }{\text{(aq)}} \to {\text{C}}{{\text{r}}_2}{\text{O}}_7^{2 - }{\text{(aq)}} + {{\text{H}}_2}{\text{O(l)}}\)

B.     \({\text{Co(}}{{\text{H}}_2}{\text{O)}}_6^{2 + }{\text{(aq)}} + {\text{4HCl(aq)}} \to {\text{CoCl}}_4^{2 - }{\text{(aq)}} + {\text{4}}{{\text{H}}^ + }{\text{(aq)}} + {\text{6}}{{\text{H}}_2}{\text{O(l)}}\)

C.     \({\text{N}}{{\text{H}}_3}{\text{(aq)}} + {{\text{H}}^ + }{\text{(aq)}} \to {\text{NH}}_4^ + {\text{(aq)}}\)

D.     \({\text{C}}{{\text{H}}_3}{\text{CO}}{{\text{O}}^ - }{\text{(aq)}} + {{\text{H}}_2}{\text{O(l)}} \to {\text{C}}{{\text{H}}_3}{\text{COOH(aq)}} + {\text{O}}{{\text{H}}^ - }{\text{(aq)}}\)

B

What is the pH of a solution in which the hydroxide ion concentration is 1 × 10⁻¹¹ mol dm⁻³ at 298 K?

K_w = 1 × 10⁻¹⁴ at 298 K

A.     3

B.     7

C.     11

D.     14

A

Which species acts as a Lewis and Brønsted–Lowry base?

A.      [Al(H₂O)₆]³⁺

B.      BF₃

C.      NH₄⁺

D.      OH⁻

D

The table below shows data for the \({{K_{\text{a}}}}\) and \({{\text{p}}{K_{\text{b}}}}\) values for some acids and bases at 298 K.

Which two formulas represent the weakest acid and the weakest base in the table?

A.     HClO and \({{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{N}}{{\text{H}}_{\text{2}}}\)

B.     \({{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{COOH}}\) and \({\text{N}}{{\text{H}}_{\text{3}}}\)

C.     \({{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{C}}{{\text{H}}_{\text{2}}}{\text{COOH}}\) and \({{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{N}}{{\text{H}}_{\text{2}}}\)

D.     HClO and \({\text{N}}{{\text{H}}_{\text{3}}}\)

A

It was thought “good to mix the data types, \({{\text{p}}{K_{\text{a}}}}\) and \({{K_{\text{a}}}}\)”. This was the fifth hardest question (60.81% correct) with the wrong answers almost equally chosen.

Which species produced by the successive dissociations of phosphoric acid, H₃PO₄, are amphiprotic?

A.     HPO₄²⁻ and PO₄³⁻

B.     H₂PO₄⁻ and HPO₄²⁻

C.     H₂PO₄⁻ and PO₄³⁻

D.     HPO₄²⁻ only

B

What is the conjugate base of phenol, \({{\text{C}}_{\text{6}}}{{\text{H}}_{\text{5}}}{\text{OH}}\)?

A.     \({{\text{C}}_6}{\text{H}}_4^ - \)–OH

B.     \({{\text{C}}_6}{{\text{H}}_5}\)–\(\mathop {\text{O}}\limits^ +  {{\text{H}}_2}\)

C.     \({{\text{C}}_6}{{\text{H}}_5}\)–\({{\text{O}}^ - }\)

D.     \({{\text{C}}_6}{\text{H}}_6^ + \)–OH

C

What are the conjugate acid–base pairs in the following reaction?

\[{\text{HCO}}_3^ - {\text{(aq)}} + {{\text{H}}_2}{\text{O(l)}} \rightleftharpoons {\text{O}}{{\text{H}}^ - }{\text{(aq)}} + {{\text{H}}_2}{\text{C}}{{\text{O}}_3}{\text{(aq)}}\]

C

If \({\text{20 c}}{{\text{m}}^{\text{3}}}\) samples of \({\text{0.1 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}\) solutions of the acids below are taken, which acid would require a different volume of \({\text{0.1 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}\) sodium hydroxide for complete neutralization?

A.     Nitric acid

B.     Sulfuric acid

C.     Ethanoic acid

D.     Hydrochloric acid

B

This question on the neutralization of an alkali by various acids proved to be a particularly good discriminator (Discrimination Index 0.68), with many of the weaker students considering that the strength of the acid would affect the amount required.

Which group of three compounds contains only weak acids and bases?

B

Which salts will dissolve in water to give solutions with a pH above 7?

I.     \({\text{N}}{{\text{a}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}\)

II.     \({\text{C}}{{\text{H}}_{\text{3}}}{\text{COONa}}\)

III.     \({\text{N}}{{\text{a}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}\)

A.     I and II only

B.     I and III only

C.     II and III only

D.     I, II and III

A

What describes HPO₄²⁻?

A.     Amphiprotic but not amphoteric

B.     Amphoteric but not amphiprotic

C.     Amphiprotic and amphoteric

D.     Neither amphiprotic nor amphoteric

C