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alkaline buffers

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    can someone please help me understand how alkaline buffers work..eg equations involved when H+ is added & when OH- is added & how it keeps the pH constant

    thank you for your help
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    (Original post by aqua05)
    can someone please help me understand how alkaline buffers work..eg equations involved when H+ is added & when OH- is added & how it keeps the pH constant

    thank you for your help
    A solution of a weak base and a salt of the weak base e.g NH3 and NH4Cl

    NH3 + H+ = NH4+

    NH4Cl + OH- = NH3 + H2O + Cl-
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    (Original post by aqua05)
    can someone please help me understand how alkaline buffers work..eg equations involved when H+ is added & when OH- is added & how it keeps the pH constant

    thank you for your help
    lets use the example CH3COO-NA+
    First we mix CH3COOH + NaOH --> CH3COO-NA+ + H20
    some CH3CHOOH remians because its in excess
    and we will obviously have some CH3COO-NA+

    so overall we have:
    CH3COOH --> <-- CH3COO- + H+

    if we add an acid it will therefore he adding H+
    this means according to le chet principle our equilibrium will shift to minimise the change so it will move in the direction where H+ is going to be minimised hence it moves to the LEFT


    if alkali is added it will therefore add OH-
    OH- + H will react to form H20
    as H+ is now used up the equilib will shift to the position to increase the conc of H+ hence it now moves to the RIGHT to generate more H+



    hope its helped you a bit
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    (Original post by asaaal)
    lets use the example CH3COO-NA+
    First we mix CH3COOH + NaOH --> CH3COO-NA+ + H20
    some CH3CHOOH remians because its in excess
    and we will obviously have some CH3COO-NA+

    so overall we have:
    CH3COOH --> <-- CH3COO- + H+

    if we add an acid it will therefore he adding H+
    this means according to le chet principle our equilibrium will shift to minimise the change so it will move in the direction where H+ is going to be minimised hence it moves to the LEFT


    if alkali is added it will therefore add OH-
    OH- + H will react to form H20
    as H+ is now used up the equilib will shift to the position to increase the conc of H+ hence it now moves to the RIGHT to generate more H+



    hope its helped you a bit
    Although that's correct, OP was asking about alkaline buffer solutions
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    (Original post by thegodofgod)
    Although that's correct, OP was asking about alkaline buffer solutions
    oh my youre right, i didnt even realise it said alkaline..ive only been awake 35 minutes.. takes me about 3 hours to feel fully alert aahahah.

    GOD HELP ME.. i have ALL morning exams this year :|

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Updated: June 8, 2012
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