Tag Info

Hot answers tagged acid-base

21

Do not do it !! ( putting acidic, or rather any juice to copper bottles ) You are in danger of copper poisoning. Generally, by food processing laws, copper is not allowed to be in direct contact with food, as there is danger of copper contamination. Especially acidic liquids, like vinegar or citrus juices, directly slowly dissolve copper in presence of ...

18

It is a semantics question with an open ended discussion. If you recall the old problem "How many angels can dance on a pinhead? Medieval problem, this issue here is similar. Basically in chemistry, all the terminology is controlled or endorsed by the International Union of Pure and Applied Chemistry (IUPAC). They have a very open ended definition of a salt:...

8

This is in reply to the following comment. but if Ayurveda recommends it.... – Poutnik The following abstract is from Journal Health Popul Nutr. 2012 Mar; 30(1): 17–21."Storing Drinking-water in Copper pots Kills Contaminating Diarrhoeagenic Bacteria" by V.B. Preethi Sudha, Sheeba Ganesan,G.P. Pazhani, T. Ramamurthy, G.B. Nair and Padma ...

7

By electrolysis. In general electrolysis is a very common way of purifying metals if you have them dissolved, since you can selectively control the reaction by adjusting the potential current. Al and Cu are also obtained through electrolysis of their salt solutions. Electrolysis is a redox reaction that occurs in the non spontaneous direction driven by a ...

7

You actually got it! The proper way to get to the (right) answer is to ask yourself which one is the conjugate base of a weak acid. If you are given more than one weak acid, you should be provided with the respective acid dissociation constants $K_\mathrm{a}$. In that case, keep in mind that the smaller (i.e. the closer to zero) the $K_\mathrm{a},$ the ...

7

We are pretty sure that acids are not considered salts Definitions in chemistry don't have to be exclusive (that is, if X is an acid, it cannot be anything else). It's not very useful to call acids "salts of hydrogen", but it's not fundamentally wrong. The entire DHMO joke is based on giving water unusual but nevertheless technically correct names.

6

You write: [..] carbonic acid. It is a compound of the ions $\ce{H+}$ and $\ce{HCO^3-}$ This is the error in your reasoning. There is a covalent bond between the hydrogen and the rest of the molecule. When it reacts as an acid, this bond breaks. I like definition d) of the online MW: any of various compounds that result from replacement of part or ...

6

Aluminium hydroxide isn't a partilarly reactive or soluble compound, so you probably don't want to directly mix it with stearic acid; also, you'd likely obtain a tristearate this way. According to a procedure described in US3056819A patent, a synthetic path would be to obtain aluminum dihydroxychloride $\ce{Al(OH)2Cl}$ first, and then add stearic acid and ...

5

There are two parts of your question. We should not mix historical medical practices with modern scientific truths. Also, this does not mean that all old medical knowledge is bad or useless. In older medicine, gold foil arsenic compounds, silver foil, crushed pearls and mercury oxides were added in medicines,. It does not mean that if these practices were ...

5

There exists a range of ω-3 acids. Fatty acids are made of a chain of carbon atoms (generally linear), with a carboxylic acid at one end. Usually the carbon atoms are linked with a single-bond, but in unsaturated acids one or more of these are double-bonds. In order to describe the positioning of these double bonds, the carbon-atoms are numbered, starting ...

4

You say: I searched everywhere, but I didn't get the answer. When I type youtube gold recovery from chloroauric acid into Google, the first link is to a Youtube video with a visible demonstration of converting chloroauric acid to gold. The video shows that metabisulfite can reduce chloroaurate to form tiny tiny grains of gold powder, as a reddish dust. ...

4

Your solution is correct up to the point you assumed that you can double the concentration of hydrochloric acid. Unfortunately, this is wrong and not at all how stoichiometry works. Let's focus on what's important. In the nutshell, we are dealing with a typical neutralization reaction: $$\ce{H3O+ + OH- <=> 2 H2O}$$ and note that $\ce{BaCl2}$ as a ...

4

As Ivan Neretin said in the comments, $\ce{H3O+}$ is already there, via the autodissociation of water: $$\ce{2H2O <=> H3O+ + OH-}\tag{1}$$ Now water reacts with the ammonia that you add, according to the equilibrium reaction you provided: $$\ce{NH3 + H2O <=> NH4+ + OH-}\tag{2}$$ This increases the hydroxide concentration further, so the first ...

3

In 1981, Nishikata et al. published Viscosities of Aqueous Hydrochloric Acid Solutions, and Densities and Viscosities of Aqueous Hydroiodic Acid Solutions in the Journal of Chemical Engineering Data. Table III from this paper shows what you are after. I don't know what temperature you used to make your density measurement, but assuming it was 20 °...

3

That is a valid question, because acid rain has been known to damage paints, particularly high-gloss, i.e. clear coat. Best would be to test the effect of vinegar on a hidden area, and double-check under bright light from different angles. Your idea to test on glass is good, because it shows how long a soak is needed. If it appears unaffected, rinse ...

3

You mentioned the strengths of the acids and bases can be used to determine whether the salt is acidic or basic. This is largely correct because a strong acid has a very weak conjugate base, while a weak acid has a relatively strong conjugate base; the same applies to bases and their conjugate acids. There are a few other rules of thumb though that can be ...

2

It is interesting to consider that either outcome is possible, depending on the order of addition. If a solution containing 0.5 moles of HCl is added to a solution of 1 mole of K2CO3, slowly, with mild stirring, cold, the products will be 0.5 KCl + 0.5 KHCO3. Nothing is lost to the atmosphere. However, if a solution of 1 mole of K2CO3 is added to a ...

2

Strong acid and strong base First, lets see where the enthalpy of $\pu{-57.3 kJ/mol}$ comes from. In aqueous solution, strong acids and bases react completely to form $\ce{H+}$ and $\ce{OH-}$, respectively. The neutralization of a strong acid with a strong base then is always the same reaction: $$\ce{H+(aq) + OH-(aq) -> H2O(l)}$$ We can calculate the ...

2

You run into all sorts of problems when the pH is outside of the range of 1 to 13. For example, in Environ. Sci. Technol. (2000) 342, p. 254-258, they say: [...] the former National Bureau of Standards (NBS) established a set of conventions that limits measurements to 1 < pH < 13 and to ionic strength, I < 0.1. The main limitations are the ...

2

Pure water dissociate according to the equation: $$\ce{2H2O(l) <=> H3O+(aq) + OH- (aq)}$$ Assume that $K_\mathrm{w} = 1.00 \times 10^{-14}$ at room temperature. Thus, $\ce{[H3O+]}$ of solution is $\pu{1.00E-7 M }$. Now, if you add a trace amount of strong acid, this equilibrium would be disturbed and backward reaction occur to reduced some of added ...

2

The logic is the same used for a monoprotic weak acid, considering the two ionization steps, as indicated by @MaxW. For a diprotic weak acid we have: The first ionization \begin{align*} \ce{H2A + H2O &<=> H3O+ + HA-} &K_{\ce{a}1}=\frac{\ce{[H3O+][HA-]}}{\ce{[H2A]}} \end{align*} and the second ionization \begin{align*} \ce{HA- + H2O &&...

2

Maybe the water spots are not limestone, chalk or gypsum, all of which are dissolvable in acid. Maybe they are mud spots, which could contain clays which adhere to the car paint. If a toilet bowl cleaner based on citric acid (stronger acid than acetic, also a chelator) or Coke (acidic, contains phosphate) do not work quickly (without damage), perhaps an ...

1

If you use tap-water together with Sodiumcarbonate, chances are that the residue is Calciumcarbonate (unless your tap-water is very soft). Calciumcarbonate is significantly less soluble in water, but can be dissolved in acid. I would try to put a bottle/arm in a hot 5% solution of acid (acetic acid is fine, personally I would prefer citric acid) to see if ...

1

Here is the density/concentration chart for aqueous $\ce{HI}$ at $\pu{20 ^\circ C}$:  \begin{array}{ccc} \hline \text{Density, }\pu{kg/L}(\text{@ }\pu{20 ^\circ C}) & \text{Concentration, %}(w/w) & \text{Concentration, }(\pu{mol/L}) \\ \hline 1.0342 & 5.2 & 0.4204 \\ 1.0812 & 10.8 & 0.9129\\ 1.1226 & 16.4 & 1.4393 \\ 1....

1

The water molecule has a 3D structure based on a $\ce{AX2E2}$, which transforms into $\ce{AX3E1}$ for the oxonium ion (refer to Gillespie's VSEPR theory). Water has a two symmetry planes, one containing both hydrogen atoms and the tilted plane where those two atoms face each other, with in the intersection the axis permitting a Debye dipole moment of $P = \... 1 You can look at the question this way: when we have a strong acid/strong base titration, at the equivalence point we would end up with a neutral solution (the$\mathrm{pH}$would be ~$7$). If we had a weak acid/strong base titration, at the equivalence point we would end up with$\mathrm{pH}$above 7 (basic solution has$\mathrm{pH}$between$8-10\$). If ...

Only top voted, non community-wiki answers of a minimum length are eligible