[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

[Melikeyflute]

(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-

[asaaal]

(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

[thegodofgod]

(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

[asaaal]

(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 :|