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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59 views

Finding the pH of the solution

In this video, at 3:30 min professor solves two equations $$\ce{H2O —> H+ + OH-}$$ and $$ \ce{HCl —> H+ + Cl-}$$ and deduces $[\ce{H+}] = [\ce{Cl-}] +[\ce{OH-}]$. How come this happen from ...
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Calculating the pH of Strong Acid Solutions [closed]

Calculate the $\mathrm{pH}$ of a $\pu{1.5e–11 M}$ solution of $\ce{HCl}.$ How is the $\mathrm{pH}~7?$
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1answer
56 views

Getting pH of a weak acid and conjugate base with a given ratio [closed]

A practice question reads What is the $\ce{pH}$ of a solution of a weak acid and its conjugate base when the ratio of the concentrations of the conjugate base/weak acid is 1/3? (the weak acid $K_\...
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1answer
22 views

The pH scale/calculating pH level [closed]

How much water do you need to add to 10 mL of a solution of HCl with a pH of 4 to change the pH to 5?
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1answer
313 views

pH value of a very dilute alkaline solution [closed]

What is the pH of a $\pu{10^-9 M}$ $\pu{NaOH}$ solution? I think it is 5.
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1answer
101 views

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
487 views

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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0answers
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How do you calculate pH, with different types of acids in solution? [closed]

New question 41.0 mL of 0.0150 M hydrochloric acid, 130 mL of 0.0650 M hydroiodic acid and 55 mL of 0.00680 M sulfuric acid are pipetted into a 250 mL volumetric flask, which is then filled up to the ...
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In the picture below, which one is acidic, alkalalinse and neutral [closed]

Which form do you think is present at acidic pH, which one in neutral solutions, and which one in alkaline solutions? Briefly justify your answers, based on the availability of protons at different pH ...
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0answers
20 views

How to calculate pH of final solution using volume and pH of initial solutions? [closed]

When two solutions of equal volume with pH 2 and 8 are mixed, what happens to resulting pH ? How to calculate the final pH? I am being too specific this time.
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1answer
411 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
119 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
141 views

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
804 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
117 views

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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1answer
272 views

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
104 views

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
206 views

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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2answers
7k views

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
56 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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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
310 views

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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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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233 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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1answer
48 views

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
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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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805 views

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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615 views

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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3answers
1k views

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 ...