Background: A precipitation reaction occurs when two soluble (dissolved) ionic solutions are mixed and form an insoluble solid called a precipitate. The remaining liquid is called the supernatant. This process is common in diagnostic testing to identify specific ions present in a patient's sample.
A student mixes aqueous Sodium Chloride (NaCl) with aqueous Lead(II) Nitrate (Pb(NO3)2).
Step 1 (Part A): Determining Possible Products
Using a double displacement logic, what are the two possible products formed by switching the ions? Click for Part A Answer
The possible products are NaNO3 and PbCl2.
Step 2 (Part B): Applying Solubility Rules
Sodium salts and Nitrates are always soluble, but Chloride (Cl-) is insoluble when paired with Lead (Pb2+). Which product is the precipitate? Click for Part B Answer
The precipitate is PbCl2(s). The resulting net ionic equation is:
Pb2+(aq) + 2 Cl-(aq) ➞ PbCl2(s)
Background: In an acid-base reaction, an acid reacts with a base to produce a salt and water. Acids are substances that create hydronium ions (H3O+) in water, while bases create hydroxide ions (OH-).
A restaurant serves lemon juice (citric acid) with fish to neutralize the odor of Cadaverine (a weak organic base).
Step 1 (Part A): Classifying the Reaction
When you mix Vinegar (Acetic acid) with Baking Soda (Sodium Bicarbonate), the reaction produces a salt, water, and CO2 gas. What two categories does this reaction fall into? Click for Part A Answer
It is both an Acid-Base (Neutralization) reaction and a Gas-Forming reaction.
Step 2 (Part B): Understanding Dissociation
HCl is a strong acid. If you place 1.0 mole of HCl in water, how much of it remains as intact HCl molecules? Click for Part B Answer
None. Because it is a strong acid, it dissociates completely into H3O+ and Cl- ions.