Scientific Tutor

What skills do I need before I start predicting the products of a precipitation reaction?

Forming the products of a precipitation reaction requires bringing together a lot of different previous skills you have learned in your chemistry class or on this website. The primary sections you need to know or should review are how to form ionic compounds and how to break apart ionic compounds and balancing chemical equations and types of chemical equations and precipitation definition and precipitation rules (solubility table). The skills in those previous sections will be talked about in detail with the examples in this section but they will be much more brief.

How do you form the products of a precipitation reaction (precipitation equation)?

Typically precipitation reactions are double displacement (double replacement) types of reactions with ionic compounds. Which means you need to rearrange the two ionic compounds in the reactants to from two new ionic compounds in the products. The information you are given is like the example below.

Predict the products of the chemical reaction (chemical equation), indicate the precipitant, and balance the equation.

Na₃PO_4(aq) + CaCl_2(aq) ——>

Answer: The precipitant is Ca₃(PO₄)₂

2 Na₃PO_4(aq) + 3 CaCl_2(aq) ——> Ca₃(PO₄)_2(s) + 6 NaCl_(aq)

Examples: Predict the products of the chemical reaction (chemical equation), indicate the precipitant, and balance the equation. Make sure to use the solubility table and precipitation definitions if you need them. Another useful tool is the ion periodic table. VIDEO Demonstration of Forming Products of a Precipitation Reaction Examples 1.

Na₂S_(aq) + AgNO_3(aq) ——>

Answer: The precipitant is Ag₂S

Na₂S_(aq) + 2 AgNO_3(aq) ——> Ag₂S_(s) + 2 NaNO_3(aq)

ZnBr_2(aq) + (NH₄)₃PO_4(aq) ——>

Answer: The precipitant is Ni₃(PO₄)₂

3 ZnBr_2(aq) + 2 (NH₄)₃PO_4(aq) ——> Zn₃(PO₄)_2(s) + 6 NH₄Br_(aq)

Ba(OH)_(aq) + VCl_3(aq) ——>

Answer: The precipitant is V(OH)₃

3 Ba(OH)_2(aq) + 2 VCl_3(aq) ——> 3 BaCl_2(aq) + 2 V(OH)_3(s)

PRACTICE PROBLEMS: Predict the products of the chemical reaction (chemical equation), indicate the precipitant, and balance the equation. Make sure to use the solubility table and precipitation definitions if you need them. Another useful tool is the ion periodic table.