Which two compounds are classified as bases by the Brønsted-Lowry definition, but not by the Arrhenius definition, and why?

a) Sodium hydroxide (NaOH) and potassium hydroxide (KOH), because they dissociate to form hydroxide ions, not hydrogen ions.

b) Ammonia (NH3) and methane (CH4) because they contain hydrogen but do not dissociate to form hydrogen ions.

c) Ammonia (NH3) and boron trifluoride (BF3), because they form a compound through the transfer of an electron pair.

d) Ammonia (NH3) and sodium carbonate (Na2CO3), because they accept hydrogen ions but lack hydroxide ions.

Question

Elisabeth Gregory

Chemistry

27 February, 08:36

Which two compounds are classified as bases by the Brønsted-Lowry definition, but not by the Arrhenius definition, and why?

a) Sodium hydroxide (NaOH) and potassium hydroxide (KOH), because they dissociate to form hydroxide ions, not hydrogen ions.

b) Ammonia (NH3) and methane (CH4) because they contain hydrogen but do not dissociate to form hydrogen ions.

c) Ammonia (NH3) and boron trifluoride (BF3), because they form a compound through the transfer of an electron pair.

d) Ammonia (NH3) and sodium carbonate (Na2CO3), because they accept hydrogen ions but lack hydroxide ions.

+3

Answers (1)

Know the Answer?

Monica Shepherd · Answer 1

b) Ammonia (NH3) and methane (CH4) because they contain hydrogen but do not dissociate to form hydrogen ions.

Explanation:

A substance will be classified as a base according to Arrhenius theory if it produces OH (-) hydroxide ions in water. Ammonia (NH3) is a basic substance, but it is not an Arrhenius base because it does not release hydroxide ions into solution, the same happens with methane (CH4), where all four hydrogens are bound very tightly to the carbon and are not going anywhere.