Wilh this form a buffer?
50 mL of .10 M HCl; 35 mL of .150 M NaOH
WORK:
Moles of HCl= .005
Moles of NaOH= .00525
total litres of solution= .05 + .035= .085 L
[HCl]= .005 mol/.085 L = .0588 M
[NaOH]= .00525 mol/ .085 L = .0618 M
Ka of HCl= 1.3*10^6
pKa= -log(1.3*10^6) = -6.114
Plug into H-H equation...
pH= pKa + log [A-]/[HA]
pH= (-6.114)+ log (.0618/.0588)
pH= -6.09???
I am stuck.. I don't think this value is supposed to be negative. How does the pH of the solution tell someone whether or not the soltion is a buffer?
Generally, calculating the pH will not tell you if the solution is a buffer or not although it may give some hints. Your best bet is to know the definition of how to prepare a buffer.
A weak acid and its salt or a weak base and its salt (or solutions that will make those) will be a buffered solution.
Therefore, acetic acid and some salt such as sodium acetate or potassium acetate will be a buffer. Alternatively, one can add NaOH to acetic acid (which makes the salt, sodium acetate) but not add enough NaOH to neutralize all of the acetic acid. That means you will have some acetic acid (a weak acid) left over and the sodium acetate the reaction provided gives the weak acid and its salt and that is a buffered solution.
A basic buffer might be NH4Cl and NH3(aq) OR NH3 plus some HCl (but not enough to neutralize all of the NH3).
So what about this solution you have? Is HCl a strong acid or a weak acid? Is NaOH a strong base or a weak base? If you don't know, look up the Ka value and Kb value in tables in your text. They will not be listed in those tables MEANING that they are a strong acid and a strong base. And that isn't the recipe for a buffer.
i don't no
To determine whether the solution is a buffer or not, we need to check the pH value and the components of the solution. A buffer solution typically consists of a weak acid and its conjugate base, or a weak base and its conjugate acid.
In this case, you have a mixture of HCl (hydrochloric acid) and NaOH (sodium hydroxide). HCl is a strong acid and completely dissociates in water, so it is not a weak acid needed for a buffer solution. NaOH is a strong base that also fully dissociates.
Since both HCl and NaOH are strong electrolytes, they completely ionize into H+ and Cl- ions and Na+ and OH- ions respectively. Therefore, the pH of the resulting solution will be determined by the excess of either H+ or OH- ions, depending on which reactant is present in excess.
In your calculation, you found that the pH of the solution is approximately -6.09. However, pH values cannot be negative in practical terms. Negative pH values typically indicate that the concentration of H+ ions is extremely high, which is not possible in this case since you started with a finite amount of HCl and NaOH.
Therefore, based on the information provided, the resulting solution is not a buffer.