[painkiller]

Is there a way to increase the concentration of a 30% H2SO4 solution ?
by vaporizing some water perhaps ?

sry if my question is dumm but although i am in love with chemistry i am a noob

[woelen]

Yes, you can evaporate out water very well. Use a GLASS heat resistent beaker and boil for a while. Do this in a good fume hood or outside, the fumes and aerosol formed are very corrosive.

Sulphuric acid and phosphoric acid are particularly good at concentrating, because the concentrated acids are liquids with high boiling point (300 C or so). You can easily rise the concentration to appr. 90%. Going higher will be much more difficult. Getting the last amount of water out of the acid is not possible for sulphuric acid, from 90% or so, the boiling point rapidly increases and at a concentration of 96%, the boiling point has risen to 300 C or so, and then the azeotrope of H2SO4 and water is boiling. So, from a practical point of view, more than 90% is not easily done.

Phosphoric acid can be concentrated in the same way, but at concentrations well above 85% this acid tends to decompose, making pyrophosphoric acid and forming all kinds of polymeric polyfosfates, which are thick syruppy and eventually dissolve your glass.

A word of warning: Concentrated H2SO4 is EXTREMELY corrosive. It chars your skin, clothes and most organics like wood, paper, in seconds. Wounds of this acid are burning and painful. Be VERY careful, especially when the acid is hot!!