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The Right Tools for the Job


The directions for an experiment being carried out to determine the molar mass of a monoprotic organic acid are as follows.

"Place 0.5 g (± 0.1 mg) of the unknown solid acid in a 125-mL Erlenmeyer flask. Add about 30 mL of distilled water and two drops of bromothymol blue indicator. Titrate the resulting solution to the bromothymol blue endpoint. "

Of the four choices listed below (not including ordinary glassware), which of the following includes ONLY those items of equipment needed to carry out this step?


Analytical balance, flask, 50-mL graduated cylinder, buret, pH meter.


50-mL graduated cylinder, flask, buret, pH meter only.


Analytical balance, flask, and buret only.


50-mL graduated cylinder, flask and​ buret only.