Experiment 1: 1. I took a 2.0 mL sample of the drain cleaner and diluted it with

ID: 709057 • Letter: E

Question

Experiment 1:

1.I took a 2.0 mL sample of the drain cleaner and diluted it with distilled water to a volume of 21.0 mL.

2.I took a 1.5 mL sample of the diluted drain cleaner and added a drop of phenolphthalein. It turned bright pink.

3.I titrated the 1.5 mL sample with 1.0 M HCl solution. It took 1.1 mL to reach the endpoint and turn the solution clear.

Experiment 2:

1.I took another 1.5 mL sample of the diluted drain cleaner and added 3.0 mL of distilled water to it.

2.I added a drop of phenolphthalein and it again turned bright pink.

3.I titrated it with 1.0 M HCl and it took 1.1 mL to reach the endpoint and turn the solution clear.

Questions:

Assuming that the 1.0 M HCl was really 1.0 M, and that my volume measurements were all correct:

1.Explain why the two titrations took exactly the same amount of HCl to reach the endpoint.

2.What was the concentration of hydroxide ion in the undiluted drain cleaner? (show your work)

What conclusions can you make about the relative amounts of sodium hydroxide and potassium hydroxide in the undiluted drain cleaner?

ok this is the concentration of diluted drain cleaner

moles of OH- = 1.0*1.1 = 1.1 moles

this is in 1.5 ml of sample

so moles in 21 ml = 21*1.1/1.5 = 15.4 mili moles

this is the number of moles of OH- initially present

initiam volume = 2ml

so concentration= 15.4/2 = 7.7M

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