Chapter 23, Problem 84A

Interpretation Introduction

Interpretation : To determine the molarity of ${\text{Ca(NO}}_{\text{3}}{\text{)}}_{\text{2}}$ in a diluted solution.

Concept Introduction : The concentration of ${\text{Ca(NO}}_{\text{3}}{\text{)}}_{\text{2}}$ can be found by using the dilution law by considering both the initial and the final volume along with the initial molarity or concentration that is given in the problem.

Answer to Problem 84A

0.116M

Explanation of Solution

According to the dilution law

  ${\text{M}}_{}{}_{\text{1}}{\text{V}}_{\text{1}}{\text{=M}}_{\text{2}}{\text{V}}_{\text{2}}$

Where ${\text{M}}_{}{}_{\text{1}}$ = initial molarity of the ${\text{Ca(NO}}_{\text{3}}{\text{)}}_{\text{2}}$ solution i.e., 0.210M

  ${\text{V}}_{\text{1}}$ = initial volume of the ${\text{Ca(NO}}_{\text{3}}{\text{)}}_{\text{2}}$ solution i.e., 250ml

  ${\text{M}}_{\text{2}}$ = Final molarity of the ${\text{Ca(NO}}_{\text{3}}{\text{)}}_{\text{2}}$ solution

  ${\text{V}}_{\text{2}}$ = Final volume of the ${\text{Ca(NO}}_{\text{3}}{\text{)}}_{\text{2}}$ solution i.e., 450ml

  $\begin{array}{l}\text{0}\text{.210M}\times {\text{250ml=M}}_{\text{2}}\times \text{450ml}\\ \text{0}\text{.210M}\times {\text{250ml / 450ml = M}}_{\text{2}}\\ \text{0}{\text{.116M=M}}_{\text{2}}\end{array}$

Conclusion

The final molarity of the ${\text{Ca(NO}}_{\text{3}}{\text{)}}_{\text{2}}$ solution is 0.116M