Answered

This formula equation is unbalanced.



$Pb \left( NO _3\right)_2( aq )+ Li _2 SO _4( aq ) \rightarrow PbSO _4(s)+ LiNO _3( aq )$



Which coefficient should appear in front of $LiNO _3$ in the balanced equation?


A1
B2
C3
D4

Verified Answer :

  • Count the atoms of each element on both sides of the unbalanced chemical equation.
  • Balance the elements systematically: Lead (Pb) and Sulfate (\(SO_4\)) are balanced first as they have a 1:1 ratio.
  • Place a coefficient of 2 in front of \(LiNO_3\) to balance the Lithium (Li) and Nitrate (\(NO_3\)) atoms on both sides.
  • Verify the balanced equation \(Pb(NO_3)_2 + Li_2SO_4 \rightarrow PbSO_4 + 2LiNO_3\).
  • The final coefficient for \(LiNO_3\) is \(\boxed{2}\).

Explanation

  1. Analysis of the Equation

The chemical equation provided is:
\[Pb(NO_3)_2(aq) + Li_2SO_4(aq) \rightarrow PbSO_4(s) + LiNO_3(aq)\]
To balance this, we count the number of atoms for each element on both sides of the equation.

Reactants:

  • Lead (Pb): 1
  • Nitrate group (\(NO_3\)): 2
  • Lithium (Li): 2
  • Sulfate group (\(SO_4\)): 1

Products:

  • Lead (Pb): 1
  • Sulfate group (\(SO_4\)): 1
  • Lithium (Li): 1
  • Nitrate group (\(NO_3\)): 1
  1. Balancing the Chemical Equation

We see that Lead (Pb) and the Sulfate group (\(SO_4\)) are already balanced. To balance Lithium (Li) and Nitrate (\(NO_3\)), we observe that the reactant side has 2 Lithium atoms and 2 Nitrate groups. The product side, in \(LiNO_3\), currently has only 1 of each. By placing a coefficient of 2 in front of \(LiNO_3\), we get:
\[Pb(NO_3)_2(aq) + Li_2SO_4(aq) \rightarrow PbSO_4(s) + 2LiNO_3(aq)\]
Now, let's verify the counts:

  • Pb: 1 on both sides.
  • \(NO_3\): 2 on the left, \(2 \times 1 = 2\) on the right.
  • Li: 2 on the left, \(2 \times 1 = 2\) on the right.
  • \(SO_4\): 1 on both sides.

The equation is now balanced with the simplest whole-number coefficients.

  1. Conclusion

Having balanced the equation as \(1Pb(NO_3)_2(aq) + 1Li_2SO_4(aq) \rightarrow 1PbSO_4(s) + 2LiNO_3(aq)\), the coefficient in front of \(LiNO_3\) is 2. The correct option is 2. The final answer is \(\boxed{2}\).

Examples

Balancing chemical equations is essential in laboratory settings for determining the exact amounts of substances needed for a reaction. For example, if a chemist wants to precipitate lead(II) sulfate by reacting lead(II) nitrate with lithium sulfate, they must know the stoichiometric ratio (1:1:1:2) to ensure no excess reactants are wasted and to accurately predict the yield of the solid precipitate. Understanding these ratios helps in everything from pharmaceutical manufacturing to water quality testing, where specific chemical proportions ensure safe and effective outcomes.

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