Questions tagged [ph]

pH (or the potential of hydrogen) is a scale used to measure how acidic or basic an aqueous solution is.

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Why can we ignore the weak conjugate base/acid when calculating the pH in a titration problem? [closed]

Take the reaction 350 mL of 0.8M HCN and 0.6M NaOH for example. The problem asks us the calculate the pH when we add 500 mL of 0.6M NaOH into the 350 mL of 0.8M HCN (This is more than enough to ...
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1answer
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Litmus paper reactions for mixed solutions [closed]

I am wondering what could cause my litmus paper to first react to the alkaline. turning blue, and then changing to an acidic red color?
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1answer
383 views

Calculating PH of solution after adding strong acid (equilibrium)

Consider the classic example when talking about acids and bases: Say you have 1M of $\ce{HCL}$ and you throw it into water, calculate the resulting pH (= concentration of $\ce{H3O+}$). The way this ...
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1answer
107 views

Determining volume of acid needed to be added to reach a specific pH

Suppose there are $\pu{0.024}$ moles of $\ce{Na2HPO4}$ in a $\pu{0.250L}$ solution. How would we calculate the amount of $\pu{0.145M}$ $\ce{HCl}$ needed to reach a $\mathrm{pH}$ of 6.60? I have ...
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2answers
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What is the ionization constant, $K_a$, of the acid?

A 0.45 M solution of a weak acid, HX, has a pH of 4.5. What is the ionization constant, $K_a$, of the acid? Attempt at solution: [HX] is already given as 0.45 M. [H+] is given by $10^{-4.5}$. ...
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1answer
152 views

pH of salt composed of the conjugate of strong acid and base

salt like [HA]B dissloves in water (here we don't consider its solubility) : $$\ce{HA <=>[$K_\mathrm a$] A- + H+}$$ and $$\ce{B- + H2O <=>[$K_\mathrm b$] HB + OH-}$$ usually we ...
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1answer
794 views

why the buffer capacity depends on the ratio of salt and acid in acidic buffer?

According to the Henderson–Hasselbatch equation when pH = Pka for any buffer solution then why we say that this is the best buffer?
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1answer
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Find the concentration of proton after adding a acid to NaOH [closed]

I have this simple problem that I cannot figure out though, only the first part. 100 ml of 1.0 $\frac{mol}{L}$ $NaOH_(aq)$ contains ( a ) g of NaOH. After mixing 100 ml of 1.0 $\frac{mol}{L}$ $...
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The Sørensen pH scale and strong acids diltution from pH 1 to pH 4 by 1000 times?

I am reading a chemistry book that makes the following point about Sørensen's pH discovery regarding [H+] being in negative powers of 10: To dilute a solution from a pH 1 to a pH 4 (just 3 pH ...
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2answers
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pH of strong acid weak acid mixture [closed]

Question: $\ce{H2S}$ ($\pu{0.1M}$; $K_\mathrm{a} = 1.2×10^{-20} $) and $\ce{HCl}$ ($\pu{0.3M}$) with same volume are mixed together. What is the resultant $\mathrm{pH}$? My approach: Let the volume ...
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1answer
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Ph of acid would be one? [closed]

I am interested in the chemical lsd or "acid". I wanted to know if lsd is acid in its pure form would that mean it is water?
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Why are ketones acidic?

I have found various sources saying that ketones are acidic (pKa=20), and then relate it to the formation of the enolate ion. However, isn't an enolate ion of a ketone basic due to the oxygen's ...
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1answer
30 views

Acid/Base Indicator [closed]

I'm not sure how the concept and math work on this problem. Can someone show me how you can get the answer, both conceptually and using math?
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1answer
53 views

neutralization of a strong acid with a strong base [closed]

When a 1M H2SO4 is mixed with an equal volume of 1M NaOH, is the mixture acidic, basic, or neutral?
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Acidify H2O with CO2 [on hold]

How many liters of $\ce{CO2}$ per liter of $\ce{H2O}$ are required to reduce the pH of water from 7.8 to 5.8? I am looking into using $\ce{CO2}$ injection as an alternative to acidify my water with ...
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1answer
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Finding the pH value of HF [closed]

Find the pH value of HF. $pH = -\log[H+]$ for strong acids $pOH = -\log[OH-]$ for strong bases $pH = 1/2(pKa - \log C)$ for weak acid $pOH = 1/2(pKb - \log C)$ for weak base HF is weak acid so $...
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1answer
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Why do some acids have pH 8? [closed]

Is it necessary for an acid to have pH less than 7? If no, please elaborate with examples.
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49 views

How does sodium carbonate reduce pH?

Sodium carbonate is used in pools to raise pH. From my understanding, it would dissociate in water like so: $$\ce{Na2CO3 <=> 2 Na+ + CO3^2-}$$ To raise pH, doesn't it have to absorb hydrogen ...
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215 views

What mass of potassium lactate is needed to 300.0 mL of 0.238 M Lactic acid solution to make a solution with a pH of 4.00? pKa (lactic acid) =3.86

Upon attempt, I've yielded an answer of 11.91g. My calculations do not take 300 mL Lactic acid solution into account, and now I somewhat know the error is at least partially due to the fact that my ...
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2answers
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How to find the equivalence point on a graph of an acid-base titration curve? [closed]

Here is the data taken from the lab: Acid pH, Vol (cm3)[ (9.67, 4cm3) (9.08, 8cm3) (8.70, 10cm3) (8.06, 12cm3) (7.93, 13cm3) (4.76, 14cm3) (2.45, 15cm3) (2.23, 16cm3) (2.10, 17cm3) (2.01, ...
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Concentration of Carbon dioxide in Blood

Let's say we're able to decrease concentration of carbon dioxide in blood, how will the pH of the blood be affected? My Reasoning : Since blood has approximately 92% water, it is safe to assume the ...
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2answers
62 views

What's wrong in this? [duplicate]

While calculating pH of $10^{-8}$M HCl, we take into account the $\ce{H^+}$ ions released by water. But water also releases $\ce{OH-}$ions.So she shouldn't they neutralise the $\ce{H+}$ ions?
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pH level in human body [closed]

For my alkaline diet, I need to maintain a pH that's above 7, I need to achieve the objective like this: I have eaten 300 g of grapefruit (pH = 13), and eaten 70 g of chocolate (pH = 5,5). What pH ...
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Where on the backbone does a peptide get protonated at low pH?

As a particular example, how does the backbone of a peptide look at $\mathrm{pH}~2$? Where does the backbone get protonated in such an acidic solution? I know that at low $\mathrm{pH}$ the free ...
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How do the numbers on the pH scale compare? [closed]

How do the numbers on the pH scale compare? Example – is a pH of 4 twice as strong as a pH of 2? Remember the pH scale is not linear! Also, "is 4 twice of 2" isn't my question. I just want to know the ...