A 12.00g sample of Addition of an excess of lead (II) nitrate to a 50.0mL solution of magnesium chloride caused a formation of 7.35g of lead (II) chloride precipitate. What was the molar concentration of chloride ions in the solution (in mol/L)?

Respuesta :

Answer: The concentration of chloride ions in the solution is 1.056 mol/L

Explanation:

The chemical equation for the reaction of lead (II) nitrate and magnesium chloride follows:

[tex]Pb(NO_3)_2+MgCl_2\rightarrow PbCl_2+Mg(NO_3)_2[/tex]

All the chloride ions are getting converted to lead (II) chloride

To calculate the number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

Given mass of lead (II) chloride = 7.35 g

Molar mass of lead (II) chloride = 278.1 g/mol

Putting values in above equation, we get:

[tex]\text{Moles of }PbCl_2=\frac{7.35g}{278.1g/mol}=0.0264mol[/tex]

1 mole of lead (II) chloride produces 1 mole of lead ions and 2 moles of chloride ions.

So, moles of chloride ions = (2 × 0.0264) = 0.0528 moles

To calculate the molarity of solution, we use the equation:

[tex]\text{Molarity of chloride ions in solution}=\frac{\text{Moles of chloride ions}\times 1000}{\text{Volume of solution (in mL)}}[/tex]

Moles of chloride ions = 0.0528 moles

Volume of solution = 50.0 mL

Putting values in above equation, we get:

[tex]\text{Concentration of chloride ions in solution}=\frac{0.0528\times 1000}{50.0}\\\\\text{Concentration of chloride ions in solution}=1.056mol/L[/tex]

Hence, the concentration of chloride ions in the solution is 1.056 mol/L