why is the buffering capacity of a titration involving weak acid/bases maximum wen pH = pKa ?
600985
According to the Henderson-Hasselbalch equation,\n\npH = pKa + log [A-]/[HA]\n\nSo, when pH = pKa, then [A-] = [HA]\n\nA buffer has is a mixture of undissociated acid and the products of dissocation.  With the concentrations equal, there is the maximum number of ions to react with to changes in pH.
564023
acid + base ---> salt + H2O
798545
A buffer is a system of two or more chemicals used to maintain a sontant pH trange.  They are usually comprised of a weka acid and its conjugate base.  The typical pH of blood is around 7.4.  The main pH buffer system in blood is between Carbon dioxide, bicarbonate ion, HCO3- and carbonic acid, H2CO3.  When dissolved in water, Carbon dioxide forms carbonic acid.  The pH of blood remains constant by allowing offgassing of CO2 when the pH gets too low (acidic).  When the pH rises, CO2 becomes more soluble in water/blood thus forming the \n\n         CO2 + H2O<-> H2CO3<-> H+  + HCO3- \n\nbuffer system.  Shifting to the right of that equation will lower the pH, shifting to the left will raise it.  This is how a very narrow biological pH range is formed.
744922
HClO2 + Ba(OH)2 -> BaClO2 + H2O\n\n2(NH4)3PO4 + 3Ca(NO3)2 -> 6(NH4)(NO3) + Ca3(PO4)2\n\nFinished and balanced.
774155
This dissociates into Cl- and\n(CH3)2NH2+\n\nCl- is an extremely weak base, so weak in fact that it is neutral\n\n(CH3)2NH2+ on the other hand is a regular weak acid that will make the solution acidic.
122756
A pH describes the amount of free H+ (or H3O+) in a solution.  A pKa value is for a given locus on a molecule, showing the degree of ionization that occurs.  For big molecules like proteins, there may be several residues taht can ionize depending on the pH, but the pH is defined for the entire solution, while the pKa values are defined for each site that can lose or gain a proton.\n\nThe pKa describes the pH at which half of the available sites will be ionized.  So the pKa values of the different loci on the protein will be known to be ionoized or not depending on pH--and this can play a major role in the structure and function of the protein.  In organic chemistry, it can also give you an idea as to the pH at which a reaction will most likely occur.
350659
Why do people answer complete and total bullcrap answers?\n\n\nThe only thing they were right about was it is a weak acid, and even that bears no relavance to its P.H only you use a diferent formula in calculating it\n\n\nthe question is incomplete, you need to know the molarity of the acid and then you get the square root of it disociation constant (Ka) multiplied by its molarity\n\nand then you -log(base10)the answer you got from the first part and that is the P.H\n\nin short  Sq root(Ka*molarity acid)= H+ concentration\n\nP.H= -logH+
835275
KOH is a strong base and HBr is a strong acid.\ngreq acid= N*V=a*M*V. HBr is monoprotic so a=1 and \ngreq acid=1* 0.1*30*10^-3=3*10^-3\n\ngreq base= a*M*V. KOH is monovalent base so a=1 and \ngreq base= 1*0.1*30*10^-3=3*10^-3\n\nYou have greq acid= greq base which means you reached the equivalence point. Since both the acid and base are strong the final pH is 7 (there is no hydolysis of the salt) -remember the H+ and OH- coming from the base and acid have completely reacted but [H+] is never 0 since you have the equilibrium for the self dissociation of water.\n\nYou could have come to the same conclusion with moles (1:1, stoichiometry, same number of moles thus neither the acid nor the base is in excess, and there is no salt hydrolysis since both are strong electrolytes) but equivalents is the best way to solve titration problems.
245193
Use your buffering equation and plug in the numbers you know to get your answer.  You might have to do reverse calulations to find your answer.
720236
1) Bi carbonate buffer system will contain HCO3- ion\n\nwhen a base is added it will liberate the H+ and produce water combining with OH- ion of the base there for reducing the effect of the base\n\nand when an acid is added it will accept the H+ ion and for H2CO3 therefor the effect of the acid will be nullified!!!\n\n2)phosphates are H2O4- or HPO42-\n\nand it will also have the functions as mentioned in the above!!\n\n3)proteins have an NH2 group and well as a COOH group both attached to the same molecule!!!\n\ntherefor when acid is added the NH2 group will neutralize it\n\nand when a base is added COOH group will neutralize it  reducing the alkalinity!\n\nthere for all these chemicals found in the blood and other body tissue will maintain the blood pH level at a constant level acting as natural buffers!!\n\nhope you understood!!!!!\n\ncheers!!
115716
Tris is generally used as a buffer to keep a chemical reaction at a stable pH. It has a pKa a 6.95 and 8.3. This means it is a polyprotic acid and base because it has two pKa, meaning it has two differnt places it can accept protons or donate protons ( you might want to review bronsted-lowry definitions). A buffer is a solution of a weak acid and weak base, since Tris is both, you only need it to create it as a buffer.\n\nTris stands for trishydroxymethyl methylamine, now you know what people never use the whole name.
841752
Probably not because albumin is a protein and in order to have a buffer you need an acid and a base. The best buffers use a weak acid and a weak base.....
172666
When a salt derived from a strong acid and a weak base dissolves in water, the solution becomes acidic. For example, consider the process\n \nNH4Cl(s) ----H2O ---> NH4+(aq) + Cl-(aq)\n\nThe Cl- ion has no affinity for H+. The ammonium ion NH4+ is  a weak conjugate acid of the base NH4+(aq) and ionizes as follows \n\nNH4+(aq) + H2O(l) <=> NH3(aq) + H3O+(aq)\n\nor simply  \n\nNH4+(aq) <=> NH3(aq)  + H+(aq)\n\nThe equilibrium constant ( or ionization constant) for this process is given by \n\n\n\nKa = Kw / kb  =   1.0*10^-14 / 1.8*10^-5 = 5.6*10^-10\n\n\n      x^2 / .10 =  5.6*10^-10\n\n           x^2  =   5.6*10^-11\n\n             x  =    7.5*10^-6 M  =  [H+]\n\npH  =  -log [H+]\n    \n    =  5.12\n\n     my answer is  C , NH4Cl
675001
pKa is the negative logarithm(-log) of ionization constant(Ka) for acids. Weak acids have partially ionized,and which have high pKa value. On the other hand strong acids is completely ionized(nearly)and they have small pKa values.
777786
what affects buffers?\n\ndepends on which bufffers  -pH will with solubility, aas will temperature\n\nmaximum capacity depends on individual buffer - citric acid maxes at 3 base molecules, as does phosphates..\n\n\nnow to the question - what will you do for me?????   Good  thing I am a Christian - so i'll just take a thank you
117935
I believe that it is 7... If the concentration of the acid and base are equal then they would probably neutralize the solution.
923865
Alright, there are two reasons \n\n1) when you add too much indicator to a titration, you are diluting the solution. Its just like if you were to add twenty drops of water to the solution, you would be changing the concentration. Changing the concentration means the titration might react differently, take much longer to complete, and the product will have a higher mass than what you would expect.\n\n2) SOME BUT NOT ALL indicators react with their solution. Phenolphthalein is an example of a chemical that does not react, (don't ask me to go over the indicators that do react, eg: adding an acid to a base shows you have a base...). If your indicator does react with your solution, then the titration will be less successful. This reason really depends what your indicator is. Bromothymol Blue is an example of an indicator that reactis with acid.