Question

Experimental Procedure, Part A. 4. What is the purpose of rinsing the pipet twice with aliquots of the saturated Ca(OH)2 solution? Experimental Procedure. Part A.4. What is the indicator used to detect the endpoint in the titration for this experiment? What is the expected color change at the endpoint in this experiment? Experimental Procedure. Part A.5. The directions are to read and record the initial volume of the buret to the correct number of significant figures. Explain what this means.

Answer 1

2. Rinsing the pippette with the same solution as the one you are going to use in your experiment ensures that you do not have an error associated with dilution effect. Say you have rinsed your pipette with distilled water prior to dipping it in a solution of Ca(OH)2. This would change the concentration of your solution due to the residual water that was present in the pipetter. Rinsing avoids this situation and gives more reporducible results.

3. a. The indicator used would be bromocresol purple.

b. the color of solution would turn yellow from initial purple at the end point.

4. The direction is to read and write the buret volume reading (intial) correctly. This is to ensure that when your end point reaches you have a correct value for the volume of titrant used to do calculations.