J17 Help

AChoudhry_1L
Posts: 55
Joined: Sat Sep 07, 2019 12:17 am

J17 Help

In each of the following salts, either the cation or the anion is a weak acid or a weak base in water. Write the chemical equation
for the proton transfer reaction of this cation or anion with water:

(a) NaC6H5O (b) KClO (c) C5H5NHCl (d) NH4Br

What are the general guidelines for solving this problem and what would the equations be?

Justin Vayakone 1C
Posts: 90
Joined: Sat Sep 07, 2019 12:19 am

Re: J17 Help

The problem is asking for equations involving a cation that is a weak acid reacting with water or an anion that is a weak base reacting with water, so they will look something like this: $\textup{A}^++\textup{H}_2\textup{O}\rightleftharpoons \textup{A}+\textup{H}_3\textup{O}^+$ or
$\textup{B}^-+\textup{H}_2\textup{O}\rightleftharpoons \textup{B}+\textup{O}\textup{H}^-$
The A represents the cation weak acid which donates an H+ to water while B represents the anion weak base receiving an H+ from water. For part a, we have Na+ and C6H5O-. Na+ doesn't react with water and just stays as ions while the anion is our weak base, so our proton transfer equation would be: $C_6H_5O^- + H_2O \rightleftharpoons HC_6H_5O + OH^-$. For part b, Oxygen is attached to Chlorine, so when this molecule dissociates in water, we'll have K+ that stays as ions and OCl- ions that will react with water: $OCl^- + H_2O \rightleftharpoons HOCl + OH^-$. For part c, C5H5NH+ will be our cation weak acid: $C_5H_5NH^+ + H_2O \rightleftharpoons C_5H_5N^- + H_3O$. For part d, NH4+ is the cation weak acid: $NH_4^+ + H_2O \rightleftharpoons NH_3 + H_3O^+$.

A Raab 1K
Posts: 56
Joined: Sat Aug 24, 2019 12:16 am

Re: J17 Help

How do you know the Cl goes with O instead of with K? (part b)