# The concentration of the quinine present in the sample to be calculated. Concept introduction: The absorbance of a solution is basically it’s ability to absorb the intensity of the light incident. The change in the concentration of the solution brings about the change in the absorbance of the solution. The change in the concentration required for the particular change in absorbance is given by: c x = A 1 c s V s ( A 2 − A 1 ) V x ### Principles of Instrumental Analysis

7th Edition
Douglas A. Skoog + 2 others
Publisher: Cengage Learning
ISBN: 9781305577213 ### Principles of Instrumental Analysis

7th Edition
Douglas A. Skoog + 2 others
Publisher: Cengage Learning
ISBN: 9781305577213

#### Solutions

Chapter 14, Problem 14.1QAP
Interpretation Introduction

## Interpretation:The concentration of the quinine present in the sample to be calculated.Concept introduction:The absorbance of a solution is basically it’s ability to absorb the intensity of the light incident.The change in the concentration of the solution brings about the change in the absorbance of the solution. The change in the concentration required for the particular change in absorbance is given by:  cx=A1csVs(A2−A1)Vx

Expert Solution

The concentration of the quinine solution is 22.0ppm .

### Explanation of Solution

The expression for the concentration of the quinine is:

cx=A1csVs(A2A1)Vx ..... (1)

Where,

• cx is the unknown concentration of quinine.
• cs is the known concentration of the solution.
• A1 is the absorbance of the quinine solution for unknown concentration.
• A2 is the absorbance of the quinine solution for known concentration.
• Vx is the volume of the unknown solution.
• Vs is the variable volume of solution.

The value of A1 is 0.636 .

The value of cs is 23.1ppm .

The value of Vs is 10.0ml .

The value of A2 is 0.903 .

The value of Vx is 25.0ml .

Substitute the values in equation (1).

cx=A1csVs( A 2 A 1 )Vxcx=( 0.636)( 23.1ppm)( 10.0ml)( 0.9030.636)( 25.0ml)=146.9166.675ppm22.0ppm

The concentration of the quinine solution is 22.0ppm .

Conclusion

Thus, the concentration of the quinine solution is 22.0ppm .

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