Download presentation

Presentation is loading. Please wait.

Published byLucas McKinney Modified over 4 years ago

1
IV. 17 Indicators p. 159-163

2
Indicator Weak organic acid or base with different colours for its conjugate acid & base forms HIn AcidIndicator

3
HIn + H 2 O = In - + H 3 O + Example Indicator: Chlorophenol Red HIn - yellow In - - red

4
When acid is added: [H 3 O + ] shifts Turns yellow HIn (for any indicator) is the form when in an acid

5
When base is added: [H 3 O + ] (combines with OH - ) shifts Turns red In - (for any indicator) is the form when in a base

6
When [Hin] = [In - ] End / Transition Point Ka= [H 3 O + ][In - ] / [HIn] = [H 3 O + ] End point = Ka for indicator pKa = - log Ka, since: »Ka = [H 3 O + ] »-log Ka = - log [H 3 O + ] »pKa = pH

7
Chlorophenol Red 5.2 - 6.8 Yellow to red Turns yellow when pH < 5.2 Turns red when pH > 6.8 Turns orange between pH of 5.2 - 6.8

8
At the midpoint of the colour change: pKa = pH = 6.0 for Chlorophenol Red Therefore, Ka = 1.0 x 10 -6

Similar presentations

OK

Calculate the pH of a solution that is 0.20 M in NaCH 3 COO and 0.10 M in CH 3 COOH. 1234567891011121314151617181920 2122232425262728293031323334353637383940.

Calculate the pH of a solution that is 0.20 M in NaCH 3 COO and 0.10 M in CH 3 COOH. 1234567891011121314151617181920 2122232425262728293031323334353637383940.

© 2018 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google