Question

You add an aqueous solution of lead nitrate to an aqueous solution of potassium iodide. Draw highly magnified views of each solution individually, and the mixed solution, including any product that forms. Write the balanced equation for the reaction.

Short answer

The balanced equation for the double displacement reaction between lead nitrate (Pb(NO₃)₂) and potassium iodide (KI) is: \[ 2 KI + Pb(NO_3)_2 \rightarrow 2 KNO_3 + PbI_2\]. In the individual solutions, lead nitrate dissociates into Pb²⁺ and NO₃⁻ ions, and potassium iodide dissociates into K⁺ and I⁻ ions. Upon mixing, Pb²⁺ ions bond with I⁻ ions to form a solid precipitate of lead iodide (PbI₂), while the K⁺ ions bond with NO₃⁻ ions to form soluble potassium nitrate (KNO₃) in the solution. The drawing should have dissociated ions in the individual solutions and a mixture of the precipitated PbI₂ and soluble KNO₃ in the combined solution.

Step-by-step solution

Identify the reaction and products

The reaction taking place is a double displacement reaction, also known as a precipitation reaction. In this case, lead nitrate (Pb(NO₃)₂) and potassium iodide (KI) will swap their anions and form new compounds. The products resulting from this reaction are lead iodide (PbI₂) and potassium nitrate (KNO₃). Now we will balance the equation to ensure equal numbers of each atom on both sides of the reaction.

Write the balanced equation

Balanced equation for the reaction is \[ 2 KI + Pb(NO_3)_2 \rightarrow 2 KNO_3 + PbI_2\] In the equation, two molecules of potassium iodide are required to react with one molecule of lead nitrate to form two molecules of potassium nitrate and one molecule of lead iodide.

Draw the individual solutions

1. Aqueous solution of lead nitrate (Pb(NO₃)₂) In this solution, the lead nitrate molecules dissociate into lead ions (Pb²⁺) and nitrate ions (NO₃⁻). The drawing should feature several pairs of Pb²⁺ ions surrounded by NO₃⁻ ions in a random arrangement. 2. Aqueous solution of potassium iodide (KI) In this solution, the potassium iodide molecules dissociate into potassium ions (K⁺) and iodide ions (I⁻). The drawing should feature several K⁺ ions surrounded by I⁻ ions in a random arrangement.

Draw the mixed solution

3. Mixed solution of Pb(NO₃)₂ and KI Upon mixing, the ions in the solutions will interact and a solid precipitate of lead iodide (PbI₂) will form while also producing potassium nitrate (KNO₃) in the solution. In the drawing, you should illustrate the following: - Pb²⁺ ions bonding with I⁻ ions, forming the solid precipitate of PbI₂. They will be present in clusters or lattice-like structures. - K⁺ ions surrounded by NO₃⁻ ions denoting the soluble potassium nitrate (KNO₃) resulting from the reaction. These ions will continue to remain distributed randomly in the solution.