Answer: The balanced equation is Pb(NO3)2 + 2KI ——-> 2KNO3 + PbI2.
Explanation: In writing chemical equations, the law of conservation of mass which states that matter can neither be created nor be destroyed in an ordinary chemical reaction must be obeyed. This means that the total mass of the reactants must be equal to the total mass of the products formed.
Pb(NO3)2 + 2KI ——-> 2KNO3 + PbI2.
The number of atoms on both sides of the equation must equal in the above equation.
The number of Pb atom is 1 on both sides. The number of N atoms is 2 on both sides. The number of O atoms on both sides is 6, the number of K atoms on both sides is 2 while the number of I atoms is 2 on both sides.
Therefore, the equation is balanced.