Questions tagged [ph]

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

Filter by
Sorted by
Tagged with
-1
votes
1answer
61 views

How do I calculate the amount of polyprotic acid and base needed to achieve a certain buffer pH?

e.g. Citric Acid and Trisodium Citrate $\ce{H3C6H5O7 <=>[ka_1] H2C6H5O7- + H+ <=>[ka_2] HC6H5O7^2- + H+ <=>[ka_3] C6H5O7^3- + H+}$ Using the definition of Ka and substituting for ...
-1
votes
1answer
3k views

Find the half equivalence point

How to find the half equivalence point knowing the pH, molarity, titrant added at equivalence point? This a fairly straightforward and simple question, however I have found many different answers to ...
-1
votes
1answer
222 views

Numerical on acetic acid - sodium acetate buffer

Starting with 1 L of 2.0 M $\ce{CH3COOH}$, we wish to make a buffer solution of pH=4.00. Consider two ways to make the buffer: a) One way would be to add sodium acetate. How many moles must be added?(...
-1
votes
1answer
1k views

pH value change with dilution

How does pH value change with dilution for the question shown in the picture? I expect the pH value to increase with dilution. Is there any case where the value remains same with dilution?
-1
votes
1answer
279 views

calculating ph of a mixture of acids

I came across a question that couldn't find the answer to and i couldn't find the answer anywhere. The question is the following. You have a soltion created by dissolving HCN and HBrO in water (T = ...
-1
votes
1answer
500 views

How to make a buffer using HClO

If we plan to prepare a buffer with the $\mathrm{pH}$ of $7.35$ using $\ce{HClO}$ ($\mathrm pK_\mathrm a = 7.54$), what mass of the solid sodium salt of the conjugate base is needed to make this ...
-1
votes
2answers
1k views

Relating pH and buffer capacity

So, here is the equation for a weak acid - strong base pH curve And here is the expression gotten when the derivative of concentration of hydronium ions with respect to volume of base added is ...
-2
votes
2answers
3k views

How to tell the pH of HC2H3O2?

Find the $\mathrm{pH}$ of a $\pu{0.500 M}$ solution of $\ce{KC2H3O2}$. I am preparing for an exam on equilibrium and I have two questions: How would I go about calculating this? Is the $\ce{H3O}$ in ...
-2
votes
2answers
186 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 ...
-2
votes
2answers
402 views

What is the pH of HCl solution at $10^{-8}$M? [duplicate]

After using the negative logarithmic value of $\ce{H^+}$ ion concentration, I get a value of pH that results in base. Can you please help me? Thank you in advance
-2
votes
1answer
1k views

Calculating pH of solution of phosphoric acid and ammonia

What is the $\ce{pH}$ of the solution created when $\ce{50ml}$ of $\ce{0.2M}$ $\ce{H3PO4}$ is mixed with $\ce{50ml}$ of $\ce{0.4M}$ $\ce{NH3}$? This problem can be approached rigorously. That's what ...
-2
votes
2answers
60 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 ...
-2
votes
1answer
27 views

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 $\mathrm{pH}~7?$
-2
votes
1answer
68 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_\...
-2
votes
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?
-2
votes
1answer
343 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.
-2
votes
1answer
113 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 ...
-2
votes
1answer
526 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?
-2
votes
1answer
439 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 ...
-2
votes
1answer
128 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 ...
-2
votes
2answers
150 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 $10^{-4.5}$. ...
-2
votes
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 ...
-2
votes
1answer
814 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?
-2
votes
1answer
120 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 $\frac{mol}{L}$ $...
-3
votes
1answer
273 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 ...
-3
votes
1answer
230 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?
-3
votes
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 ...
-3
votes
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?
-3
votes
1answer
58 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?
-3
votes
1answer
1k views

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 $...
-3
votes
1answer
311 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.
-3
votes
1answer
63 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 ...
-3
votes
1answer
262 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 ...
-4
votes
2answers
2k views

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, ...
-4
votes
1answer
49 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 ...
-4
votes
2answers
63 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?
-5
votes
3answers
835 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 ...
-6
votes
2answers
680 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 ...
-7
votes
3answers
2k 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 ...