Question

Complete a net ionic equation for each proton-transfer reaction using curved arrows to show the flow of electron pairs in each reaction. In addition, write Lewis structures for all starting materials and products. Label the original acid and its conjugate base; label the original base and its conjugate acid. If you are uncertain about which substance in each equation is the proton donor, refer to Table \(4.1\) for the relative strengths of proton acids. (a) \(\mathrm{NH}_{3}+\mathrm{HCl} \rightleftharpoons\) (b) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{O}^{-}+\mathrm{HCl} \rightleftharpoons\) (c) \(\mathrm{HCO}_{3}^{-}+\mathrm{OH}^{-} \rightleftharpoons\) (d) \(\mathrm{CH}_{3} \mathrm{COO}^{-}+\mathrm{NH}_{4}{ }^{+} \rightleftharpoons\)

Short answer

Question: In the proton-transfer reaction NH₃ + HCl -> NH₄⁺ + Cl⁻, identify the original acid and base, their conjugates, and draw Lewis structures for all starting materials and products. Answer: In this reaction, NH₃ is the original base and HCl is the original acid. NH₃ forms the conjugate acid NH₄⁺, and HCl forms the conjugate base Cl⁻. The Lewis structures are as follows: NH₃: H | H - N - H | [lone pair] HCl: H - Cl NH₄⁺: H | H - N - H || H Cl⁻: [Cl]⁻ with 8 electrons around it (full octet)

Step-by-step solution

Identify the acid and the base

In this reaction, NH₃ is the base as it accepts a proton, and HCl is the acid as it donates a proton.

Complete the net ionic equation

The net ionic equation for this reaction is: NH₃ + HCl -> NH₄⁺ + Cl⁻

Show the flow of electron pairs with curved arrows

The electron pair on the nitrogen atom of NH₃ is attracted to the hydrogen atom of HCl, as shown with the curved arrow: NH₃ + HCl -> NH₄⁺ + Cl⁻ [lone pair on N] -> [H of HCl]

Draw Lewis structures for all starting materials and products

Here are the Lewis structures for NH₃, HCl, NH₄⁺, and Cl⁻: [NH₃]: H | H - N - H | [lone pair] [HCl]: H - Cl [NH₄⁺]: H | H - N - H || H [Cl⁻]: [Cl]⁻ with 8 electrons around it (full octet)

Label the original acid its conjugate base and the original base its conjugate acid.

In this reaction, HCl is the original acid which forms the conjugate base Cl⁻, and NH₃ is the original base which forms the conjugate acid NH₄⁺.