# Tag Info

3

Easy marks for phenolphthalein usability are: $99.9\%$ of acetic acid is titrated at about $$\mathrm{pH} = \mathrm{p}K_\mathrm{a} + \log{1000} = 7.75$$ $100\%$ of acetic acid is titrated at $$\mathrm{pH} = 7 + \frac12 \cdot (\mathrm{p}K_\mathrm{a} + \log c) = 9.385 + \frac12 \log c$$ Phenolphthalein color transition is $8.2-10.0.$

0

I am first going to do the ‘flip side’ of the OP’s scenario and then basically flip it back. So we start with a 0.1 M aqueous solution of benzoic acid and the initial solution volume is 25 mL. Benzoic acid is a monoprotic weak acid with $\mathrm{p}K_\mathrm{a} = 4.20$. The initial pH is 2.606. The strong base used for the titration is 0.1 M NaOH. At the ...

0

Ringo has given an excellent answer for your questions and continued to direct you during comment session. I just want to tell you is, this question can also be answered by using Henderson–Hasselbalch equation. Suppose after titrating, the equilibrium concentrations of BH is $\alpha$ and $\beta$ at pH 8.1 and 7.5, respectively. Thus, all [BH] comes from the ...

2

I am afraid, direct acid-base titration is not the right way to analyze aspirin exactly because of the you stated - hydrolysis. The rule number no of any titration is that there should be no side reaction and it should go to completion almost instantly. The direct titration of aspirin is problematic because hydrolyzes pretty fast to salicylic acid- an ...

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Can you please elaborate on that part? I know that the E value of Mno4- is +1.51, and the one for BrO3- is +1.48. What does that suggest?? that Mno4- will more likely to be reduced by Fe+ than Bro3-?? please explain The first and foremost hint, even before you calculate the electrode potentials is the solubility rule taught in general chemistry. ...

1

The question This is the question, corrected according to Poutnik's comment, and adding (i) and (ii) to distinguish the two scenarios: $\ce{NH3}$ solution of $\pu{0.1 mol dm-3}$ is being added to a $\pu{25.0 cm3}$ of $\pu{0.1 mol dm-3}$ $\ce{HCl}$ solution. Calculate the pH of the solution when volume of added $\ce{NH3}$ solution is (i) \$\pu{25.0 ...

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Where concentration matters ( burette ) there is rinsing to achieve stable and constant concentration. Where amounts matters ( flask ) there is no rinsing to achieve stable and constant amount.

-1

If you were to calculate the concentration of acid from the titration, and you add distilled water to the erlenmeyer flask, then yes, you would affect the [H3O+(aq)] since increasing volume with same number of moles decreases the concentration of the solute (or analyte) and thus increases the pH of the solution (because pH is -log(hydronium conc.)), ...

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