Question

Assuming complete precipitation of AgCl, calculate the sum of the molar concentration of all the ions if 2l of 2M $A{g}_{2}S{O}_4$ is mixed with 4l of 1M NaCl solution is

• A. 4 M
• B. 2 M
• C. 3 M
• D. 2.5 M

Answer 1

Answer: (B)

The explanation for the correct option:

Option(B)

• The precipitation reaction of silver chloride is given as:

$A{g}_{2}S{O}_{\text{4}}+2NaCl⟶2AgCl+N{a}_{2}S{O}_4$

• Concentration of $A{g}_{2}S{O}_{\text{4}}$ = 2M

• Volume of $A{g}_{2}S{O}_{\text{4}}$ =2L

• Hence from the molarity number of moles can be calculated as:

  $M=\frac{n}{v}$

  $2M=\frac{n}{2L}$

  $n=2\times 2=4moles$

• Concentration of $NaCl$ = 1M
• Volume of $NaCl$ =4L

$M=\frac{n}{v}$

$1M=\frac{n}{4L}$

$n=1\times 4=4moles$

Hence, $NaCl$ is the limiting agent.

Number of moles of $N{a}_{2}S{O}_4$ formed = 2 moles

Hence the total concentration of ions in the solution= 2moles per litre