Question

Classify each cation as weak acid or pH-neutral:

(a) Li⁺
(b) CH³NH³
(c) Fe³⁺

Answer 1

Li+ is pH-neutral as it comes from a strong base, CH3NH3+ is a weak acid as it's the conjugate acid of methylamine, and Fe3+ is a weak acid since it hydrolyzes to donate protons.

Step-by-step explanation:

To classify each cation as a weak acid or ph-neutral, let's look at each one individually:

1. Li+ - Lithium ion comes from LiOH, lithium hydroxide, which is a strong base. Thus, when Li+ is in solution, it does not react with water to form an acid, making it pH-neutral.
   
2. CH3NH3+ - This is the methylammonium ion, which is the conjugate acid of a weak base (methylamine, CH3NH2). Therefore, it can donate a proton in solution, making it a weak acid.
   
3. Fe3+ - The iron(III) ion can also cause the solution to become acidic as it tends to hydrolyze, forming hydrated iron(III) ions that can donate protons to water. Thus, it is considered a weak acid.