Chapter 15, Problem 30A

Interpretation Introduction

Interpretation:

The factor that decreases the concentration of salt solution needs to be explained.

Concept Introduction:

The equation of dilution is given as,

  $M_1{V}_1=M_2{V}_2$

Where, $M_1$ is the molarity in initial conditions while $M_2$ is the molarity of the solution in final conditions. Similarly, $V_1$ is the volume of the solution in initial conditions while $V_2$ is the volume in final conditions.

Answer to Problem 30A

Correct answer: A. Add water to the solution.

Explanation of Solution

Reason for correct option:

The molarity equation of the diluted solution is,

  $M_1{V}_1=M_2{V}_2$

In the dilution process, due to the addition of the extra water to the salt solutions, the total volume of the solutions is increased but the number of moles of solute is remains the same in the solution.

Conclusion

Reason for incorrect options;

For B: No, due to the sink drain, the volume of the solution is decreased concentration does not get affected.

For C: Volume and number of moles both increases due to the addition of more sodium chloride.

For D: No, if the salt solution is kept open in the air, water gets evaporated and solution becomes even more concentrated.

For E: No. Only option A is correct.