Evaporation of acid solution

[Primarygun]

What happens if I boil a beaker of hydrochloric acid ?

[MulderMan]

Presumably the HCl (g) will boil off first and you will be left with water. Depends on how hard you heat it.

[YT2095]

by boiling, you lower the vapor pressure, and the HCl evaporates.

 

but as above, it depends on how long and how hot (it will boil at less than 100c).

[Primarygun]

The ions of this covalent compound with simple molecular structure combine together when water leaves? Then, the gas leaves?

[jdurg]

by boiling' date=' you lower the vapor pressure, and the HCl evaporates.

 

but as above, it depends on how long and how hot (it will boil at less than 100c).[/quote']

 

Actually, wouldn't it boil at a higher temperature due to the dissolved ions in solution? I always thought it was freezing point depression and boiling point elevation.

[YT2095]

no, think of Alc in water, it`ll boil at less than 100c also, but freeze at a lower temp too.

it all depends on the addative

[raivo]

HCl makes azeotrope with water. This boils at 108.6 C and contains 20% of HCl and 80% water. If you start to boil hydrochloric that has more than 20% concentration you get at first lot of gaseous HCl. When concentration changes to 20% HCl and H2O will evaporate together and concentration does not change any more. If you boil long enough you get empty pot.

[coquina]

One of the few terms I remember from chemistry:

 

http://en.wikipedia.org/wiki/Anhydride

 

"The anhydride is so called because it may be formed from an acid by the removal of water."

 

Out of curiosity - if the HCL boils off too - how do you remove the water to form the anhydride?

[YT2095]

adding it to conc sulphuric acid and re-distilling it is one way, vacuum distillation is another, but personaly I`de make a salt of the acid and mix it with sulphuric and distill it.

 

and also ravio is correct, you`ll never end up with a pure water state, he says 20% i`de have to look that up, but have no reason to disbeleive him. after that it all just evaporates at the same rate. I should have added that bit really.

 

Quite pointless really ))

[jdurg]

no' date=' think of Alc in water, it`ll boil at less than 100c also, but freeze at a lower temp too.

it all depends on the addative [/quote']

 

If you boil a mixture of alcohol and water, the solution will boil at a higher temperature depending on the concentration. (When the water is the higher concentration, then it will boil at a temperature above the normal B.P. of water. Once the alcohol becomes a higher concentration, the water becomes the solute and the solution will boil at a higher temperature than the pure alcohol would). The only way to lower the boiling point of a substance is to lower the air pressure above it. There is no other way. Science has proven that time and time again.

[Primarygun]

If you boil a mixture of alcohol and water, the solution will boil at a higher temperature depending on the concentration.

How about alloy of metal?

adding it to conc sulphuric acid

Copper(II) sulphate is soluble in water and in sulphuric acid, isn't it?

Why does it becomes insoluble when the water of crystallization of hydrated copper(II) sulphate is drawn by con. sulphuric acid?

Moreover, when does copper(I) or copper(II) ion becomes green in colour? In which solution? Aqueous Copper(II) nitrate?

[YT2095]

Jdurg, How do you explain making Moonshine then?

[jdurg]

Jdurg, How do you explain making Moonshine then?

 

That's because ethanol and water form an azeotrope at about 95% ethanol. However, at that point it's no longer a solution of ethanol in water. It's a solution of water in ethanol. When you're talking about moonshine, the solution at that point is basically all ethanol with a little bit of water. This is able to form an azeotrope. At this point, however, saying that the alcohol has lowered the boiling point of water is fictitious since nearly all of the water is gone from the solution.

[YT2095]

well we know the BP of pure water is 100c when pure, so I supose technicaly NOTHING can lower its BP other than negative pressure, this is understood.

 

my point is that: "Although the boiling point of ethanol, 78.3 degC, is significantly lower than the boiling point of water, 100 degC, these material cannot be separated completely by distillation. Instead, an azeotropic mixture (i.e. a mixture of 95% ethanol and 5% water) is obtained, and the boiling point of the azeotrope is 78.15oC. In a distillation, the most volatile material (i.e. the material that has the lowest boiling point) is the first material to distill from the distillation flask, and this material is the azeotrope of 95% ethanol which has the lowest boiling point."

 

taken from : http://www.ucc.ie/ucc/depts/chem/dolchem/html/comp/ethanol.html

 

also it`s freezing point is lowered too.

 

maybe we`re actualy debating the same side here?

[jdurg]

Lol. In a twisted sort of way, I think we might be. How about we both say that we're right and we rule?

[YT2095]

works for me

[Primarygun]

Anyone is free to answer me?

[budullewraagh]

How about alloy of metal?

it depends on the alloy

 

Copper(II) sulphate is soluble in water and in sulphuric acid, isn't it?

Why does it becomes insoluble when the water of crystallization of hydrated copper(II) sulphate is drawn by con. sulphuric acid?

Moreover, when does copper(I) or copper(II) ion becomes green in colour? In which solution? Aqueous Copper(II) nitrate?

the answer to all your questions is simple: cupric salts hydrate easily. the hydrated sulfate is soluble because there is so much water coordinate covalently bonded to the cupric cation, keeping the sulfate anion away. the colour changes are because of changes in charge and hydration.