Acid-Base Lab: Explain the results presented in experiment 1. What is the differ

Question

Acid-Base Lab: Explain the results presented in experiment 1. What is the difference between “at rest” exhalation and “after exercise” exhalation? Explain in detail why there is a difference in the two results. Experiment 1: A solution was made consisting of 100 mL of distilled water, 10 drops of 0.1N NaOH and 5 drops of phenol red indicator. The solution at this point was red. Amember of the team then exhaled into the solution until the solution turned orange and then yellow. The time it took for this color transition was 96 seconds. The same initial solution was made again the same way. Again, the solution was red. The same person performed vigorous exercise for about 3 minutes. Immediately after the exercise s/he exhaled into the solution until the solution turned orange and then yellow. The time it took for this color transition was 28 seconds this time. 1. [ 5 pts ] Explain the results presented in Experiment 1 What is the difference between "at rest" exhalation and "after exercise" exhalation? Explain in detail why there is a difference in the two results.

Explanation / Answer

Here in this experiment, exhaled air cotain carbondioxide which reacts with water and form carbonic acid, carbonic acid started to neutralize NaOH solution and when enough carbonic acid is produced complete neutrilization of NaOH solution occurs which result in change in color of indicator from red to orange. If more carbonic acid production continued, then solution becomes acidic which causes change in color from orange to yellow.

Here in case first, when person at rest exhaled air into the NaOH solution, it takes more time to change the color because at rest condition, the breathing rate is slow and also the carbondixide content of each exhalation air is too less and thus it takes more time to change the color.

In case second, when person after exercise exhaled air into NaOH solution, it takes less time to change the color because in this condition the rate of breathing is high and also the carbondioxide content of each exhalation is high which takes less timne to provide sufficient amount of carbondioxide to change the color.

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