Question

Complete a net ionic equation for each proton-transfer reaction using curved arrows to show the flow of electron pairs in each reaction. Label the original acid and its conjugate base; then label the original base and its conjugate acid. (a) \(\mathrm{NH}_{4}{ }^{+}+\mathrm{OH}^{-} \rightleftharpoons\) (b) \(\mathrm{CH}_{3} \mathrm{COO}^{-}+\mathrm{CH}_{3} \mathrm{NH}_{3}{ }^{+} \rightleftharpoons\) (c) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{O}^{-}+\mathrm{NH}_{4}^{+} \rightleftharpoons\) (d) \(\mathrm{CH}_{3} \mathrm{NH}_{3}{ }^{+}+\mathrm{OH}^{-} \rightleftharpoons\)

Short answer

Question: Write the net ionic equations for the following proton-transfer reactions, identifying the original acids, bases, and their conjugate acids and bases. Also, indicate the flow of electron pairs. (a) \(\mathrm{NH}_{4}^{+}+\mathrm{OH}^{-}\rightleftharpoons\mathrm{NH}_{3}+\mathrm{H}_{2}\mathrm{O}\) (b) \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}+\mathrm{CH}_{3}\mathrm{COO}^{-}\rightleftharpoons\mathrm{CH}_{3}\mathrm{NH}_{2}+\mathrm{CH}_{3}\mathrm{COOH}\) (c) \(\mathrm{NH}_{4}^{+}+\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{O}^{-}\rightleftharpoons\mathrm{NH}_{3}+\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{OH}\) (d) \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}+\mathrm{OH}^{-}\rightleftharpoons\mathrm{CH}_{3}\mathrm{NH}_{2}+\mathrm{H}_{2}\mathrm{O}\) Answer: (a) Net ionic equation: \(\mathrm{NH}_{4}^{+}+\mathrm{OH}^{-}\rightleftharpoons\mathrm{NH}_{3}+\mathrm{H}_{2}\mathrm{O}\); Original acid: \(\mathrm{NH}_{4}^{+}\); Original base: \(\mathrm{OH}^{-}\); Conjugate acid: \(\mathrm{H}_{2}\mathrm{O}\); Conjugate base: \(\mathrm{NH}_{3}\); Electron flow: O (OH-) to N (NH4+). (b) Net ionic equation: \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}+\mathrm{CH}_{3}\mathrm{COO}^{-}\rightleftharpoons\mathrm{CH}_{3}\mathrm{NH}_{2}+\mathrm{CH}_{3}\mathrm{COOH}\); Original acid: \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}\); Original base: \(\mathrm{CH}_{3}\mathrm{COO}^{-}\); Conjugate acid: \(\mathrm{CH}_{3}\mathrm{COOH\); Conjugate base: \(\mathrm{CH}_{3}\mathrm{NH}_{2}\); Electron flow: O (CH3COO-) to N (CH3NH3+). (c) Net ionic equation: \(\mathrm{NH}_{4}^{+}+\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{O}^{-}\rightleftharpoons\mathrm{NH}_{3}+\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{OH}\); Original acid: \(\mathrm{NH}_{4}^{+}\); Original base: \(\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{O}^{-}\); Conjugate acid: \(\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{OH}\); Conjugate base: \(\mathrm{NH}_{3}\); Electron flow: O (CH3CH2O-) to N (NH4+). (d) Net ionic equation: \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}+\mathrm{OH}^{-}\rightleftharpoons\mathrm{CH}_{3}\mathrm{NH}_{2}+\mathrm{H}_{2}\mathrm{O}\); Original acid: \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}\); Original base: \(\mathrm{OH}^{-}\); Conjugate acid: \(\mathrm{H}_{2}\mathrm{O}\); Conjugate base: \(\mathrm{CH}_{3}\mathrm{NH}_{2}\); Electron flow: O (OH-) to N (CH3NH3+).

Step-by-step solution

Identify the original acid, base, and their respective conjugates

In this reaction, the original acid is \(\mathrm{NH}_{4}^{+}\) and the original base is \(\mathrm{OH}^{-}\). After the proton transfer, we get their respective conjugates, which are \(\mathrm{NH}_{3}\) and \(\mathrm{H}_{2}\mathrm{O}\).

Write the net ionic equation

The net ionic equation for this reaction is: \(\mathrm{NH}_{4}^{+}+\mathrm{OH}^{-}\rightleftharpoons\mathrm{NH}_{3}+\mathrm{H}_{2}\mathrm{O}\)

Indicate the flow of electron pairs

In this reaction, electron flow occurs from the oxygen atom of \(\mathrm{OH}^-\) to the nitrogen atom of \(\mathrm{NH}_{4}^+\). The curved arrow is drawn, starting from the lone pair on the oxygen atom and ending on the N-H bond of the \(\mathrm{NH}_{4}^{+}\). (b)

Identify the original acid, base, and their respective conjugates

In this reaction, the original acid is \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}\) and the original base is \(\mathrm{CH}_{3}\mathrm{COO}^{-}\). After the proton transfer, we get their respective conjugates, which are \(\mathrm{CH}_{3}\mathrm{NH}_{2}\) and \(\mathrm{CH}_{3}\mathrm{COOH}\).

Write the net ionic equation

The net ionic equation for this reaction is: \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}+\mathrm{CH}_{3}\mathrm{COO}^{-}\rightleftharpoons\mathrm{CH}_{3}\mathrm{NH}_{2}+\mathrm{CH}_{3}\mathrm{COOH}\)

Indicate the flow of electron pairs

In this reaction, electron flow occurs from the oxygen atom of \(\mathrm{CH}_{3}\mathrm{COO}^{-}\) to the nitrogen atom of \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}\). The curved arrow is drawn, starting from the lone pair on the oxygen atom and ending on the N-H bond of the \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}\). (c)

Identify the original acid, base, and their respective conjugates

In this reaction, the original acid is \(\mathrm{NH}_{4}^{+}\) and the original base is \(\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{O}^{-}\). After the proton transfer, we get their respective conjugates, which are \(\mathrm{NH}_{3}\) and \(\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{OH}\).

Write the net ionic equation

The net ionic equation for this reaction is: \(\mathrm{NH}_{4}^{+}+\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{O}^{-}\rightleftharpoons\mathrm{NH}_{3}+\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{OH}\)

Indicate the flow of electron pairs

In this reaction, electron flow occurs from the oxygen atom of \(\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{O}^{-}\) to the nitrogen atom of \(\mathrm{NH}_{4}^{+}\). The curved arrow is drawn, starting from the lone pair on the oxygen atom and ending on the N-H bond of the \(\mathrm{NH}_{4}^{+}\). (d)

Identify the original acid, base, and their respective conjugates

In this reaction, the original acid is \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}\) and the original base is \(\mathrm{OH}^{-}\). After the proton transfer, we get their respective conjugates, which are \(\mathrm{CH}_{3}\mathrm{NH}_{2}\) and \(\mathrm{H}_{2}\mathrm{O}\).

Write the net ionic equation

The net ionic equation for this reaction is: \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}+\mathrm{OH}^{-}\rightleftharpoons\mathrm{CH}_{3}\mathrm{NH}_{2}+\mathrm{H}_{2}\mathrm{O}\)

Indicate the flow of electron pairs

In this reaction, electron flow occurs from the oxygen atom of \(\mathrm{OH}^-\) to the nitrogen atom of \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}\). The curved arrow is drawn, starting from the lone pair on the oxygen atom and ending on the N-H bond of the \(\mathrm{CH}_{3}\mathrm{NH}_{3}^{+}\).