Question

You have a 750mL of a buffer solution that is composed of NH3 and NH4Cl with...

You have a 750mL of a buffer solution that is composed of NH3 and NH4Cl with a Kb value 1.8x 10^5 and a pH 9.43...... How many mL 6.00M HCl can be added before the buffer is exhausted?

0 0
Add a comment Improve this question Transcribed image text
Answer #1

this is a NH3-NH4+ buffer

pKb = -log(1.8*10^-5) = 4.75

pKa = 14-4.75= 9.25

then..

pH = pKa + log(NH3/NH4+)

9.43 = 9.45 + log(NH3/NH4+)

10^(9.43 - 9.45 ) = (NH3/NH4+)

0.95499 = (NH3/NH4+)

assume total NH3 + NH4+ mix is = 1 M then

mol of NH3 + NH4+ = 0.75 mol

0.95499 = (NH3/NH4+)

NH3 = 0.95499 *NH4+

0.95499 *NH4++ NH4+ = 0.75

NH4+ = 0.75/(0.95499 +1) = 0.3836 mol

mol of NH3 --> 0.95499 *0.3836 = 0.36633

then

max amount of HCl possible --> mol of NH3

0.36633 mol of HCl

V = mol/M = (0.36633)/(6) = 0.061 = 61 mL max...

this assume total molarity of buffer = 1 M

Add a comment
Know the answer?
Add Answer to:
You have a 750mL of a buffer solution that is composed of NH3 and NH4Cl with...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions
ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT