I just need help with the "solution" par of my table and numbers, 1,3 and 5. Thanks!! I know i typed a lot, I just wanted to explain my experiment. Please ask if something does not make sense thanks! Okay so here was my experiment:
In a 96 well reaction plate,
I added 6 drops of distilled water to wells A1 through A5, and then the same to wells B1 to B5.
Then I put 3 drops of 0.1 M acetic acid into wells C1 through C5 and then also to wells D1 through D5.
Then, I added 3 drops of 0.1 M sodium acetate to wells C1 thru C5 and also to D1 to D5. These wells now have a pH of 4.8.
Then i added 1 drop of bromophenol blue indicator to wells A1 thru A5, and also to C1 thru C5.
Then I put small strips of phenolphthalein indicator paper, which test for pH level to wells B1 thru B5, and also to wells D1 thru D5.
Then I put 2 drops of 0.1 M HCl into wells A1, B1, C1, and D1. Then I added 1 drop of 0.1 M HCl into wells A2, B2, C2, and D2.
Then I put one drop of 0.1 M NaOH to wells A4 to D4. Then lastly I added 2 drops of 0.1 M NaOH to wells A5 thru D5.
Row and column Solution 1 2 3 4 5
A Yellow Yellow Purple/Blue Purple/Blue Purple/Blue
B white/clear white/clear white/clear red/pink red/pink
C blue/yellow purple/blue purple/blue purple/blue purple/blue
D white/clear white/clear white/clear white/clear white/clear
What goes in the solution spot? Is that the pH?
1. How did the pH of the buffer in well C3 or D3 compare with the theoretical value of 4.8?
2. How much did the pH of water change when HCl was added? The pH went up and became much more acidic It went from about 7 to a pH of 3 or 4 in wells A1 and A2. B1 and B2 have the same pH of about 7. C1 and C2 have a pH of about 12(alkaline) and D1 and D2 also have a pH of 7, which did not change.
3. Compare this with the pH change of the buffer when HCl was added. Look for the change in pH when the HCl was added, not just the pH. Compare column 1 with 3 and 2 with 3. The pH ranges are as follows: bromophenol blue, 3.0 yellow to 4.6 purple, and phenolphthalein, 8.3 clear to 10.0 red. The pH of pure water is 7.
4. How much did the pH of water change when NaOH was added? A4 and A5 did not change, but still have a pH of about 14. B4 and B5 changed from a neutral 7 to a pH of about 0 or 1 which is very acidic. C4 and C5 did not change and still have a pH of about 14. D4 and D5 still have a neutral pH of about 7. (But D4 and D5 were red/pink at first when i added the NaOH, then quickly faded into clear. )
5. Compare this with the pH change of the buffer when NaOH was added. Look for change in pH when the NaOH was added. Compare column 3 with column 4 and column 3 with column 5.