Question

Balance the following chemical reaction: \( Pb(NO_3)_2 + KI \longrightarrow PbI_2 + KNO_3 \)

Hint:

In double displacement reactions, try balancing the polyatomic ions (like \( NO_3 \)) as single units first to simplify the process.

Answer 1

Step 1: Understanding the Concept:
A balanced chemical equation must have the same number of atoms of each element on both the reactant and product sides to satisfy the Law of Conservation of Mass.
Step 2: Detailed Explanation: Initial count:
Reactants: \( Pb=1 \), \( N=2 \), \( O=6 \), \( K=1 \), \( I=1 \)
Products: \( Pb=1 \), \( N=1 \), \( O=3 \), \( K=1 \), \( I=2 \)
Step-by-step balancing:
1. To balance Iodine (\( I \)), put a coefficient of 2 before \( KI \). Now \( I=2 \) and \( K=2 \) on the left.
2. Now Potassium (\( K \)) is 2 on the left and 1 on the right. Put a coefficient of 2 before \( KNO_3 \).
3. Check Nitrogen and Oxygen: On the right, we now have 2 atoms of \( N \) and 6 atoms of \( O \) (from \( 2 \times KNO_3 \)). This matches the left side.
Step 3: Final Answer:
The balanced equation is: \( Pb(NO_3)_2 + 2KI \rightarrow PbI_2 + 2KNO_3 \).