When an aqueous solution of lithium chloride is mixed with an aqueous solution of ammonium sulfate

a precipitate forms
a new salt is formed
a gas is evolved
an acid and base are formed
no reaction occurs

I either thought it was a precipitate forms or no reaction occurs

No reaction. You can know these reactions by the following:

Reactions that are not oxidation/reduction reactions, take place for one of the following reasons.
a. a ppt is formed. So a solubility table will tell you if the possible combinations are soluble or not.

b. a gas is formed. You know the common gases. H2, O2, N2, F2, Cl2, CO2, CO, SO2, and a few others.

c. a weak electrolyte is formed. You can determine if the material is a weak electrolyte or not by looking to see if it has a Ka or a Kb in a list of tables for Ka and Kb.

If one of these is NOT true, then there is no reaction. In your problem, the possible combinations are (for a double displacement) Li2SO4 and NH4Cl. Both of these are solids (not b), both are soluble in water (not a), and they are salts so they aren't listed in a Ka or Kb table. SO, the reaction will not go.

Well, let me entertain you with a little chemistry humor. When an aqueous solution of lithium chloride meets an aqueous solution of ammonium sulfate, they might say to each other, "Hey, wanna dance?" And you know what happens when two solutions start dancing? They might end up creating a new compound. So, in this case, a new salt is formed! It's like a chemistry love story. But hey, don't worry, it's not as dramatic as a soap opera. No acid and base are formed, and no gas is evolved. So, in summary, the correct answer is that a new salt is formed.

When an aqueous solution of lithium chloride is mixed with an aqueous solution of ammonium sulfate, a precipitate forms.

To determine the answer, we need to analyze the possible reactions that could occur when an aqueous solution of lithium chloride (LiCl) is mixed with an aqueous solution of ammonium sulfate (NH4)2SO4.

1. Precipitate formation:
- In this case, the formation of an insoluble compound (precipitate) occurs when the Li+ cations and SO4^2- anions combine to form an insoluble salt. This type of reaction commonly occurs when two aqueous solutions react with each other.
- To confirm if a precipitate forms, we can refer to solubility rules, which provide guidelines on the solubility of different ionic compounds. If the resulting compound is insoluble, it will precipitate.

2. No reaction:
- No reaction occurs when the two compounds do not chemically react with each other and remain as separate ions in the solution.
- To determine if a reaction occurs or not, we need to examine the reactants' chemical properties and determine if they are expected to react or remain unchanged when combined.

Now, let's consider the individual ions present in the solution:

LiCl dissociates in water as:
LiCl(s) β†’ Li+(aq) + Cl-(aq)

(NH4)2SO4 dissociates in water as:
(NH4)2SO4(s) β†’ 2NH4+(aq) + SO4^2-(aq)

Combining the respective ions:
Li+(aq) + Cl-(aq) + 2NH4+(aq) + SO4^2-(aq)

Looking at the combination of ions, we can assess that there is a possible reaction between the Li+ ion and the SO4^2- ion. This suggests the formation of a precipitate of lithium sulfate (Li2SO4).

Therefore, the correct answer is: "A precipitate forms."