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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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Hydrate formation and pKa of acid

It is given in my book that hydrate formation takes place only if the $\mathrm{p}K_\mathrm{a}$ value of acid is more than that of the surrounding. I didn't get why that is so. The $\mathrm{pH}$ at ...
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2answers
377 views

How to find the pH of acetic acid after adding sodium hydroxide?

$3\cdot 10^{-2}\ \mathrm{mol}$ of $\ce{NaOH}$ are added to a $1\,\mathrm{l}$ solution of $2\cdot10^{-2}~\mathrm{M}\ \ce{CH3COOH}$. Find the $\mathrm{pH}$ of the solution. I don't understand why my ...
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Why is phenol more acidic than an alcohol i.e C6H11OH [on hold]

As the title asks, why is phenol more acidic than an alcohol but less than a weak carboxylic acid
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1answer
33 views

Why is the pH level of carbonation loss decreasing then increases afterwards?

We have done an experiment of the titration of unsealed sprite soda to find the amount of carbonic acid being loss on various duration (0 to 1 hour), due to decrease pressure. The calculation was to ...
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12k views

What is exactly the pH value of distilled water?

This was asked by one of my students in my class. I know it is the pH of 7, but others say it can be 6.55 pH
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1answer
43 views

Calculate the pH of buffer solution

PROBLEM: A solution was prepared by mixing $\pu{25.00 mL}$ of $\ce{NaOH}$ $\pu{(c = 1mol/L)}$ and $\pu{10.00 mL}$ of acetic acid $\pu{(c = 2.5 mol/L)}$ in water to give $\pu{250 mL}$ of solution. ...
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20k views

Determine the pH of mixture of two weak acids

We’ve two solutions : Solution 1 $\ce{HCOOH}$ its concentration is $c_1=10^{-2}\ \mathrm{mol/l}$ and its volume is $v_1 = 50\ \mathrm{ml}$ and its $\mathrm{pH}_1 = 2.9$ Solution 2 $\ce{CH_3COOH}$ ...
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Finding the ph of a compound dissolved in aqueous solution [closed]

Which compound, when dissolved in aqueous solution, has the highest pH? A. NaCl B. Na2CO3 C. NH4Cl D. NH4NO3 How do you find the pH of a solution without having given the concentrations of the ...
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44 views

What is the pH of 0.00028 M KOH? Is this solution acidic, basic, or neutral? [closed]

My Teacher doesn't know how to teach chemistry, so I'm a week from finals and am teaching myself the entire years worth. Any help would be appreciated.
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0answers
40 views

Is it possible to raise pH in RO water without Na, Mg, K, Ca, S addition?

Maybe the question in the title is simple (=stupid) and the answer is 'simple No' but I have the urge to ask. Some background, I have an aquarium which I use RO water and I use some portions of $\ce{...
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2answers
51 views

pH of strong acid weak acid mixture

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
39 views

Calculating molecular weight of an acid based on given values of mass, volume, pH and pKa

This is what I thought was an easy problem but according to a given answer I am doing it wrong: $\pu{11 mg}$ of a monoprotic acid was dissolved in $\pu{0.5 l}$ of water. The resulting $\mathrm{pH}$ ...
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1answer
81 views

Why do weak acids like ethanol not act as a strong base in water?

In water, ethanol has a $\mathrm{p}K_\mathrm{a} = 15.9$ which means that its $\mathrm{p}K_\mathrm{b}$ is $-1.9$. Which implies that all weak acids in water are in fact strong bases. But this is not ...
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Calculating pH of solution

What is the $\mathrm{pH}$ when you dissolve equal amounts of $\ce{NaHCO3}$ and $\ce{Na2CO3}$ in water? When both of the compounds are dissolved, we will have equal amounts of $\ce{HCO3-}$ and $\ce{...
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1answer
63 views

Calculating the ph of an unknown solution by measuring the precipitate [closed]

You have an unknown metal hydroxide, but no meters or indicators. You have lead (II) nitrate, which is soluble in it, and lead (II) hydroxide that is insoluble in it. You take one liter of the unknown ...
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1answer
71 views

Calculate pH of a buffer solution

Calculate the pH in a buffer prepared from $\pu{50 mL, 0.30 M}$ formic acid ($\ce{HCOOH}$) and $\pu{30 mL, 0.40 M}$ sodium formate ($\ce{HCOONa}$). My way of solving: $n_{\ce{HCOOH}} = 0.05 \times ...
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1answer
176 views

How accurately does (pKa1 + pKa2) / 2 estimate the pH of an amphoteric salt?

This question came up when answering Find the pH and amphiprotic salt is added to water at room temperature. If we dissolve $\ce{NaHA}$ in water, the species $\ce{HA-}$ can act as acid or base: $$ \...
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1answer
324 views

In the graph provided, which of the substances is the most efficient in acting as an antacid?

If every dot represents the addition of 0.1 g of the respective base. I suppose that the best would be the one that reaches the highest pH, in the shortest time, for example Calcium Carbonate, but if ...
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1answer
32 views

Calculating pH of weak base and strong acid: Why is K(a) not required?

Question: 35mL of 1.5M $\ce{HCN}$, a weak acid(K(a)= $6.2*10^{-10}$) is mixed with 25mL of 2.5M $\ce{KOH}$. Calculate the pH of final solution. The solution given in my textbook is as follows:- $\ce{...
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1answer
31 views

Could this solution be resolved by titration?

I have a mixture of $\ce{NH_4NO_3}$ and $\ce{NH_3}$ at $\ce{pH}$ of about 13. It is possible to determine the concentration of both on them by acid-base titration? I was told it's possible, and that ...
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2answers
4k views

Is there a pH range for “neutral” detergents?

There exist many home made pH scales like these But do any of you know if there is an "official" scale that defines if a neutral detergent is 7 sharp or within a range _______?
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1answer
29 views

When there is an increase in temperature, how is the pH of the ocean affected? (Question is related to ocean acidification)

This is my current understanding: Ocean acidification is the result of atmospheric $\ce{CO2}$ dissolving in the ocean's water. When this occurs the $\mathrm{pH}$ of the ocean decreases (from the ...
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1answer
24 views

pKa value of an indicator

Can we deduce the actual value of $\mathrm{p}K_\mathrm{a}$ of an indicator if the $\mathrm{pH}$ range has been given? I know that $\mathrm{pH}$ range is physically the range of values over which an ...
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1answer
190 views

How to make an alkaline wax mixture?

I want to treat a wax so that it has an alkaline pH of at least 10. I tried just mixing sodium hydroxide with beeswax but the sodium hydroxide reacted with the beeswax and changed its properties. I ...
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2answers
37 views

Citric acid and ammonium nitrate

Soil based question. I have soil with to much Ammonium Nitrate in it. I am wondering if I use citric acid and water mixed will that flush out the extra Ammonium Nitrate that has built up in the soil. ...
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6answers
219 views

How to calculate pH of basic salt solution mixed with strong base?

Calculate $\mathrm{ pH }$ of $\pu{ 0.05 mol }$ of $\ce{Zn(CH3COO)2}$ and $\pu{ 0.025 mol }$ of $\ce{ NaOH }$ dissolved in $\pu{ 1 L }$ of distilled water? I tried to use the systematic method by ...
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1answer
58 views

Why is maximum buffer capacity for some diprotic buffers not when pH = pKa?

According to Rajkovic et al. [1]: $$β = \frac{[\ce{H+}]}{K_\mathrm{w}} + 2.303\cdot\frac{[\ce{H+}]\cdot K_\mathrm{a}\cdot c}{[\ce{H+}] + K_\mathrm{a}}$$ where $K_\mathrm{a}$ is the ...
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2answers
31 views

Can I use the Henderson–Hasselbalch for calculating the pH of non-buffer systems?

Can I use the Henderson–Hasselbalch equation on reactions that are not buffers? When I read up on the derivation of the equation, I noticed that there is absolutely no assumption on the relative ...
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1answer
44 views

pH After Titration

50mL $\ce{SO2}$ titrated with 0.1M of $\ce{KBrO4}$ with reaction: $$\ce{KBrO4 + 4SO2 + H2O -> 4H2SO4 + KBr}$$ The equivalent point is reached when the volume of $\ce{KBrO4}$ is used as much 50mL. ...
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Impact of pH? Change in Binding Affinity of protein-ligand complex based on pH and Kd?

When the $\mathrm{pH}$ was $5.0$, the temperature was $\pu{25 °C}$,the $K_\mathrm{D}$ was $\pu{5 μM}$, and [L] was equal to $K_D$, the protein(s) were half bound. If $K_\mathrm{D} = \pu{20 μM}$ ...
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3answers
563 views

Can solid acids and bases have pH values? If not, how are they classified as acids or bases?

This answer states $\mathrm{pH}$ is the aqueous concentration of $\ce{H3O+}$ or $\ce{H+}$ ions in soution. I would not say that ice lacks $\ce{H3O+}$ and $\ce{OH-}$ ions as ice's structure would ...
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1answer
30 views

At what acid concentration does potassium metabisulfite react?

I'm in the process of developing a well preserved food-stuff containing potassium metabisulfite and a number of acids (acetic, ascorbic, malic, tartaric, citric, lactic). Wine-making literature ...
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1answer
81 views

pH of CH3COOH + HCl solution (shouldn't be a buffer)

$\pu{0.05 L}$ of a solution containing $\pu{0.3 M}$ acetic acid $(\ce{CH3COOH}$, $K_\mathrm{a} = \pu{1.8e-5})$ are added to $\pu{75 mL}$ of a solution containing $\pu{0.02 M}$ hydrochloric acid ($\ce{...
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2answers
121 views

Weight of sodium acetate required to get to certain pH

How many grams of $\ce{CH3COONa}$ we need to dissolve in $\pu{2.50 L}$ of water to get a solution with $\mathrm{pH} = 9.00$? Given $K_\mathrm{a}(\ce{CH3COOH}) = 1.75\cdot 10^{-5}$ Like solving a ...
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1answer
54 views

pH of a Calcium Hydroxide vs Magnesium Hydroxide solution [closed]

In an AQA 2017 Chemistry paper, a $0.0131 \pu{mol}\cdot\pu{dm^-3}$ saturated solution of calcium hydroxide is prepared and then the question asks to predict the pH of a similar solution of magnesium ...
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1answer
87 views

How do I calculate the hydronium ion concentration if I know the strontium hydroxide concentration?

This is my first question so I would appreciate feedback on how to ask better questions. Forgive me if I don't know how to properly format math/chem. The guide is confusing. I was taking a practice ...
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1answer
103 views

Determining the reduction potential of a half cell reaction at a given pH

$E^\circ_\ce{Cu^2+|Cu} = \pu{0.34 V}$. What will be reduction potential at $\mathrm{pH} = 14$ for the same couple? Given that $K_\mathrm{sp}$ of $\ce{Cu(OH)2}$ is $10^{-19}$. My Attempt I think ...
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2answers
47 views

Calcium Phosphate Dissolution

For what reason does Calcium Phosphate dissolute at low pH? What makes it pH dependent? This question arised after reading about the calcium phosphate bridges in casein micelles and how they 'break ...
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1answer
45 views

By how many pH units does rain vs distilled water change a soil pH test?

Sources state that the concentration of $\ce{H2CO3}$ in rain is of a few µmol; I don't know if that's per ml. The buffering effect of most soils is >1000 µmol $\ce{H+}$/kg. Is the difference from low ...
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1answer
229 views

Calculate mass concentration of Ca(OH)2 solution

Can anyone help me calculate the mass concentration of $\ce{Ca(OH)2}$ solution with molar mass $\pu{74.1 g/mol}$ at the $\pu{pH of 12.8}$. My work so far: From the pH I get the molar concentration ...
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0answers
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Preparation of Copper (II) Sulfate Pentahydrate Solution

how would you make a solution of Copper (II) Sulfate Pentahydrate to achieve 150, 200, 250 and 300 mgL−1 concentration of copper? I do not have the anhydrous version of the solute. Also, when I ...
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2answers
21 views

Influence of pH on precipitate crystallite sizes?

It's normally assumed that a higher pH of solution would slow nucleation rates and hence lead to larger crystal formation. I've found literature that it is due to solid-liquid inter-facial tension. ...
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0answers
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Naming convention for buffer solutions/systems

Is there an official naming convention to follow for buffer solutions/systems? I've noticed that the name of the buffer usually just follows the name of the salt (ex. sodium acetate buffer), but what ...
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1answer
51 views

Formation of silica from TEOS

Usually tetraethyl orthosilicate/tetraethoxy silane (TEOS) is mixed with both ethanol and water to produce silica in a sol-gel process. I am curious what happens if one adds TEOS to water at a high pH,...
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1answer
34 views

Reference Books on Electrolysis and Chemical Titration process [closed]

I'm in a General Chemistry course in college. We have laboratory, and then we are supposed to make a report on what we did, etc. I'm not entirely sure what the last laboratory was about, but it was ...
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1answer
102 views

Calculate pH at equivalence point [closed]

Calculate the pH at the equivalence point of a titration of 62 mL of 0.1 M $\ce{CH_3NH_2}$ with 0.20 M HCl. The $\ce{K_b}=4.4\cdot10^{-4}$. At the equivalence point, the moles of CH3NH2 equals the ...
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1answer
39 views

Can buffer solutions be used to control the pH of ethanol?

For my experiment, I want to investigate the effect of differing pH on the solubilities of a sparingly soluble drug. However, the solubility is too low for me to conduct a reliable study on the ...
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1answer
44 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
36 views

Adding weak acid to strong base, find pH [closed]

30mL 3M acetic acid (pka 4.7) is added to 50mL 2M NaOH. what is the resulting pH a) <2 b) between 2 and 7 c) 7 d) >7 ans =d can someone explain how to actually solve for pH? the solution ...
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1answer
54 views

Using electrolysis of water as a proton generator [closed]

I'm working on a project right now, where the challenge is to try to use electrolysis as a way of controlling the $\ce{pH}$ of water. I've set up an experiment where I have two separate chambers or ...