The reaction solution is tested with litmus paper in gravimetric method to determine pH value of the solution.
Step-by-step explanation
Gravimetric method is quantitative method used to determine the weight of substance dissolved in a solvent chemically.
The substance is reacted chemically with the solvent and then the resultant substance is filtered to get the component followed by the measure of the weight of the desired substance.
The litmus paper is used to check the pH value of reaction solution.
The color change in the litmus paper decides the nature of the reaction solution.
The reaction solution is acid in nature, if the litmus paper turn in red color and the solution is base in nature if the litmus paper converts into blue color.