H2SO4 (sulphuric acid) is often used as a dehydrating agent.Then why not H3PO4 and HNO3 ?????
In other words, why H2SO4 is a better dehydrating agent than H3PO4 and HNO3???
Lets see how many of u know the correct answer.The first one to give the correct answer will be chosen as the best answer and will be awarded 10 points.
2006-09-10 03:20:56 · 10 answers · asked by i_Abhishek 2 in Science & Mathematics ➔ Physics
This is because H2SO4 has such a high affinity for water that it even abstracts 2 H and 1 0 from the other compounds.
eg.
C6H22O11 + H2SO4------------> 6 C + 11 H2O
The reaction of H2SO4 with water ( HYDRATION) is thermodynamically very favourable ;much more than the other two .
HNO3 has only one dissociation so its a weaker dehydrating agent than H2SO4 which has two.
H3PO4 also drives out but one molecule of water
2006-09-10 05:14:22 · answer #1 · answered by Ami 1 · 2⤊ 0⤋
H2SO4 is a powerful dehydrating agent than HNO3 & H3PO4 because it can rmove elements of water from substances effectivley.
2006-09-10 10:32:16 · answer #2 · answered by Anonymous · 0⤊ 1⤋
H2SO4 has the capacity to absorb water i.e.H2O.Sulphuric acid exists as H2SO4.H2O(with water of crystallisation).Whereas H3PO4 or HNO3 do not exhibit this property
2006-09-10 22:25:36 · answer #3 · answered by subhapradha s 1 · 0⤊ 1⤋
Sulphuric acid (concentrated only) has affinity for water and hence it is a good dehydrating agent.
Look up the equation for
Sulphuric acid + Water = ?
It is in most chemistry books.
2006-09-10 10:28:24 · answer #4 · answered by minootoo 7 · 0⤊ 1⤋
Sulphuric acid has a higher dissasociation constant. It readily ionises to 2H+ and (SO4 )2- . Moreover conc. sulphuric acid exists in its molecular state and only in its dilute form is it ionic.
Phosphoric acid has a lesser dissasociation constant than either sulphuric or nitric acids. The ionisation of the acid in water happens relatively slowly(in three different steps)
The properties of nitric acid lies between those of sulphuric acid and phosphoric acid. So naturally sulphuric acid is preferred.
2006-09-10 10:39:19 · answer #5 · answered by Anonymous · 2⤊ 0⤋
it is b'coz H2SO4 has a gr8 affinity for water as compared to HNO3. It readily removes water not only from materials which contain it but also eliminates hydrogen (H2) and oxygen (O2) from other compounds in the proportions req. to form water (H2O)
2006-09-10 10:30:56 · answer #6 · answered by tulip 4 · 0⤊ 1⤋
Its because sulphuric acid has such an extremely high affinity for water that it will remove hydrogen and oxygen atoms from almost any molecule or mixture of molecules that contains them.
2006-09-10 10:30:57 · answer #7 · answered by Anonymous · 0⤊ 1⤋
because the properties of H2SO4 are different from the other two
the property of H2SO4 is such that it can be used as an dehydrating agent.
while the other two cant
well
i know that much only.
2006-09-10 10:32:15 · answer #8 · answered by Anonymous · 0⤊ 2⤋
Is it an examination?
2006-09-10 10:24:07 · answer #9 · answered by dwarf 3 · 0⤊ 1⤋
this question will not come in your exam
100% sure!!!!!!!!!!!!11
2006-09-11 01:31:15 · answer #10 · answered by sami1989 2 · 0⤊ 1⤋