PART III

Add KOH dropwise to the warm solution.

1 M KOH

photo shows a graduated test tube containing approximately 1.25 mL of clear solution; next to the test tube is a translucent plastic reagent bottle labeled “1 M KOH”

video shows a small amount of clear liquid being removed from a graduated test tube with a glass pipette; a single drop of this liquid is added to a small Erlenmeyer flask sitting in a nearby sandbath; the clear liquid drips down the side of the flask to meet the small amount of amber solution visible in the flask; a gloved hand lifts the flask out of the sand bath and swirls it briefly, which transforms the amber transparent solution into an off-white cloudy mixture; a new pipette is then dunked in the off-white cloud mixture and touched to a strip of pH paper resting on the lab bench; this first touch does not leave any solution behind, so the process is repeated, at which point a dark green spot at the leftmost side of the pH paper appears; also visible in the frame is the container of pH paper, which features a key indicating the colors associated with a pH of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12

adding KOH and sampling pH

pH measurement

photo shows a strip of pH indicator aper on a black lab bench, weighted down on either side by a graduated cylinder and a small beaker; a dark green spot is visible at the leftmost end of the pH paper; also in frame is the container of pH paper that shows the color codes associated with a pH of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12

What should you do next?

Continue adding KOH.

Cool the mixture to room temperature.

Page updated

Report abuse