December 27, 2024, 12:31:37 AM
Forum Rules: Read This Before Posting


« previous next »
Pages: [1]   Go Down

Topic: How could I make a buffer solution if I only had the weak base NH3 and HCl?  (Read 2276 times)

0 Members and 1 Guest are viewing this topic.

Offline LackOfNames34

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
How could I make a buffer solution if I only had the weak base NH3 and HCl?
« on: May 03, 2021, 10:50:06 AM »
I'm not sure how to answer this. Someone briefly explained that adding 1 mol of HCl and 2 mol of NH3 would lead to an NH3/NH4 buffer. But I don't really understand that. Any help?
Logged

Offline Babcock_Hall

  • Chemist
  • Sr. Member
  • *
  • Posts: 5715
  • Mole Snacks: +331/-24
Re: How could I make a buffer solution if I only had the weak base NH3 and HCl?
« Reply #1 on: May 03, 2021, 10:51:54 AM »
A good place to start is to write a balanced chemical equation.
Logged

Offline LackOfNames34

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
Re: How could I make a buffer solution if I only had the weak base NH3 and HCl?
« Reply #2 on: May 03, 2021, 11:23:04 AM »
Ok so a balanced equation would be NH3+HCl = NH4 + Cl
Logged

Offline penta-d

  • Regular Member
  • ***
  • Posts: 15
  • Mole Snacks: +1/-0
  • Gender: Male
  • Reluctant biochemist
Re: How could I make a buffer solution if I only had the weak base NH3 and HCl?
« Reply #3 on: May 03, 2021, 12:29:02 PM »
Logged

Offline LackOfNames34

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
Re: How could I make a buffer solution if I only had the weak base NH3 and HCl?
« Reply #4 on: May 03, 2021, 12:58:36 PM »
I'm still a little bit lost. So we would react the NH3 and HCL to form NH4Cl. But how does this lead to NH3 +H2O = NH4 +OH?
Logged

Offline Meter

  • Full Member
  • ****
  • Posts: 268
  • Mole Snacks: +14/-5
  • Take what I say with a grain of salt
Re: How could I make a buffer solution if I only had the weak base NH3 and HCl?
« Reply #5 on: May 03, 2021, 01:40:49 PM »
Quote from: NoCreativeNames on May 03, 2021, 12:58:36 PM
I'm still a little bit lost. So we would react the NH3 and HCL to form NH4Cl. But how does this lead to NH3 +H2O = NH4 +OH?
1 mole of HCl reacts with 2 moles of NH3. By the end, all your HCl will be gone but you will have an equilibrium mixture of NH3 and it's conjugated acid, NH4+.
Logged

Offline LackOfNames34

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
Re: How could I make a buffer solution if I only had the weak base NH3 and HCl?
« Reply #6 on: May 03, 2021, 01:56:39 PM »
Ohh so by doing so, I would be reacting the HCl w NH3 to completion. And the equilibriums for the NH3 and the conjugate acid Nh4+ would be

NH3 + H2O <—> NH4+ + OH-

Or

NH4+ <—> NH3 + H+

Logged

Offline Meter

  • Full Member
  • ****
  • Posts: 268
  • Mole Snacks: +14/-5
  • Take what I say with a grain of salt
Re: How could I make a buffer solution if I only had the weak base NH3 and HCl?
« Reply #7 on: May 03, 2021, 02:39:34 PM »
Quote from: NoCreativeNames on May 03, 2021, 01:56:39 PM
Ohh so by doing so, I would be reacting the HCl w NH3 to completion. And the equilibriums for the NH3 and the conjugate acid Nh4+ would be

NH3 + H2O <—> NH4+ + OH-

Or

NH4+ <—> NH3 + H+
So you are adding a strong acid to an aqueous solution of ammonia. What exactly is happening?
Logged

Offline LackOfNames34

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
Re: How could I make a buffer solution if I only had the weak base NH3 and HCl?
« Reply #8 on: May 03, 2021, 02:44:01 PM »
Wouldn't the added acid be consumed in the buffer solution? Did I make an error?
Logged

Offline Meter

  • Full Member
  • ****
  • Posts: 268
  • Mole Snacks: +14/-5
  • Take what I say with a grain of salt
Re: How could I make a buffer solution if I only had the weak base NH3 and HCl?
« Reply #9 on: May 03, 2021, 02:47:10 PM »
Quote from: NoCreativeNames on May 03, 2021, 02:44:01 PM
Wouldn't the added acid be consumed in the buffer solution? Did I make an error?
The protons from the acid would react with ammonia to form NH4+, but after the reaction is over, an equilibrium will be reached. Your question is which equilibrium is reached, correct?
Logged

Offline LackOfNames34

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
Re: How could I make a buffer solution if I only had the weak base NH3 and HCl?
« Reply #10 on: May 03, 2021, 02:49:02 PM »
Yes, furthermore the pH would not have changed much if im not mistaken since NH4+/NH3 is a buffer solution
Logged

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27887
  • Mole Snacks: +1816/-412
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: How could I make a buffer solution if I only had the weak base NH3 and HCl?
« Reply #11 on: May 03, 2021, 03:36:35 PM »
Quote from: NoCreativeNames on May 03, 2021, 02:44:01 PM
Wouldn't the added acid be consumed in the buffer solution?

Why would that matter?

What is the acid in your buffer solution? What is the base?
Logged
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline Babcock_Hall

  • Chemist
  • Sr. Member
  • *
  • Posts: 5715
  • Mole Snacks: +331/-24
Re: How could I make a buffer solution if I only had the weak base NH3 and HCl?
« Reply #12 on: May 03, 2021, 04:07:40 PM »
Quote from: NoCreativeNames on May 03, 2021, 02:49:02 PM
Yes, furthermore the pH would not have changed much if im not mistaken since NH4+/NH3 is a buffer solution
This seems like the key point to me.
Logged
Pages: [1]   Go Up
« previous next »
Sponsored Links