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(show all your works for all questions) an environmental technician collects a s

ID: 1008141 • Letter: #

Question

(show all your works for all questions)

an environmental technician collects a sample of rainwater. back in the lab, her pH meter isn't working, so she uses indicator solutions to estimate the pH. a piece of Litmus paper turns red. she then divides sample into thirds and obtains the following results: Phenolphalein is colorless, Bromcresol-Green is blue, Methyl Red is orange. estimate the pH of the rainwater sample using the picture below.

pH 7 2 4 8 10 11 12 1314 Crystal violet Thymol blue 4Dinitrophenol Bamophenol blue omacresol green Methyl red Alizarin onothymol blue Phenol red Phenolphthaleir Alzarin yellow R gure 19.6 Colors and 136 Colors and approximate pH ranges of some common acid-base indicators.

Explanation / Answer

-Since the litmus paper turns red and the solution becomes colorless with the addition of phenolphthalein suggests that the rain water is acidic ie pH < 7.

- Since the solution turns blue with bromocresol green and orange with methyl red, as per the indicator chart, the pH should be around 5