Question

B. The following questions are from today's experiment: EQUL 307: pH, Acids, and Bases Use the table to answer your questions: 0.1 M solution Methyl orange Methyl Violet Phenolphthalein Thymolphthalein pH range 3.1 to 4.4 0.5 to 2.0 8.0 to 9.B 9.3 to 10.5 Color change red to yellow yellow to violet colorless to red colorless to blue yellow light pink colorless NaNO, кон violet violet yellow red blue 1. Is a 0.1 M solution of KOH acidic or basic? What experimental evidence supports your answer? KOH is acidic because it changed to blue When Thymolphthalein was the indicator. 2. List the solution that is acidic among the two KOH 3. What experimental evidence supports your above answer? 4. The identification labels fell off test tubes, each containing a colorless solution. A student knew that one of them is 0.1 M HCI, another is 0.1 M NaOH and the third is an indicator phenolphthalein solution. They are labeled as A, B, and C. He performed the following tests and listed his observations. Determine which label should be attached to each test tube. Mixture Observations Clear, no change Solution turns red (1) 1 Drop "A" + 1 Drop "B" (2) Solution from (1) + 1 Drop "C" (3) Solution from (2) + 1 Drop "B" Solution becomes clear A is Cis

Answer 1

1) KOH is basic. Because Thymolphthalein solution is blue which occur at high pH thus solution is basic.

2) None of the solution is acidic.

3) Because Thymolphthalein solution is blue and Phenolphthalein solution is light pink hence NaNO3 is neutral.

4) A is NaOH

B is HCl (Because solution become colorless on adding it in step 3)

C is Phenolphthalein (because solution turn red on adding it in step 2)