• Congratulations to the Class of 2024 on your results!
    Let us know how you went here
    Got a question about your uni preferences? Ask us here

sulfurous acid exists? (1 Viewer)

YannY

Member
Joined
Aug 28, 2007
Messages
190
Gender
Male
HSC
2008
Can someone help me with this?

Does Sulfurous acid exist in acid rain? My teacher tells me that it does not and that it changes into sulfuric acid. I was wondering how that change occurs.

ta
 

jcurry

Member
Joined
Mar 6, 2008
Messages
237
Location
Rouse Hill
Gender
Male
HSC
2008
from what i gather about it, it is formed from sulfur dioxide dissolving in water
yet there has never been any solid evidence that this occurs
but if it does form from sulfur dioxide dissolving inwater than i suppose it could be in acid rain, or normal rain as its said to be a weak acid
idk thats about all i could find out about it, maybe someone else knows more about
hope i helped
 

undalay

Active Member
Joined
Dec 14, 2006
Messages
1,002
Location
Ashfield
Gender
Male
HSC
2008
from conquering chemistry:

Sulfur dioxide reacts to form sulfurousacid :

SO2 + H2O -> H2SO3

In water droplets various other impurities in air catalyse the conversion of sulfurous acid to sulfuric acid:

2H2SO3 + O2 -> 2H2SO4 (with catalyst)

It's a bit vague, hope it help though.
 

yorkstanham

Member
Joined
Nov 2, 2007
Messages
120
Location
Woonona
Gender
Male
HSC
2008
hey, yes sulfurous acid does occur in acid rain, however it is quickly reacted and forms sulfuric acid

First sulfur dioxide reacts with water to form sulfurous acid
<SUB><SUB>SO<SUB>2</SUB> + H<SUB>2</SUB>O + H<SUB>2</SUB>SO<SUB>3 </SUB>
</SUB></SUB>
Impurities in the rain droplets then catalase the reaction and allow oxygen to react with the sulfurous acid causing sulfuric acid

2H<SUB>2</SUB>SO<SUB>3 </SUB>+ O<SUB>2</SUB> + 2H<SUB>2</SUB>SO<SUB>4</SUB>
<SUB>This sulfuric acid then dissolves in the rain casuing it to be acidic

Hope that helps
</SUB>
 

undalay

Active Member
Joined
Dec 14, 2006
Messages
1,002
Location
Ashfield
Gender
Male
HSC
2008
the reason why people say it "doesn't" exist.
Is because the actual molecule H2SO3
Can't be identified on its own.

SO2 + H2O -> H+ + HSO3-

The whole molecule doesnt exist.
 

jcurry

Member
Joined
Mar 6, 2008
Messages
237
Location
Rouse Hill
Gender
Male
HSC
2008
undalay said:
the reason why people say it "doesn't" exist.
Is because the actual molecule H2SO3
Can't be identified on its own.

SO2 + H2O -> H+ + HSO3-

The whole molecule doesnt exist.
oh k
cool thanx
 

Tiffanys

Executed member
Joined
Aug 8, 2006
Messages
270
Location
Sydney, Australia
Gender
Female
HSC
2008
Chemistry Contexts:

S + O2 --> SO2 (combustion)

SO2 + H2O --> H2SO3 sulfurous acid formation

Sulfur dioxide readily oxidised to give sulfur trioxide
2SO2 +O2 --> 2SO3

SO3 +H2O --> H2SO4 sulfuric acid formation
 

undalay

Active Member
Joined
Dec 14, 2006
Messages
1,002
Location
Ashfield
Gender
Male
HSC
2008
It can form both ways, only sulfur trioxide is not in the syllabus, so your way is redundant.
 

Tiffanys

Executed member
Joined
Aug 8, 2006
Messages
270
Location
Sydney, Australia
Gender
Female
HSC
2008
Most sulfuric acid is manufactured, but it can also occur naturally. For example, most sulfur dioxide released into the earth’s atmosphere is oxidised and dissolved in water to form the sulfuric acid in acid rain. If the acid rain results from volcanic eruption it could be regarded as natural, but if acid rain results from smelting of sulfide ores, it could be regarded as manufactured.
Ed: from hsc online
 

undalay

Active Member
Joined
Dec 14, 2006
Messages
1,002
Location
Ashfield
Gender
Male
HSC
2008
Where i can't find it.

most sulfur dioxide released into the earth’s atmosphere is oxidised and dissolved in water to form the sulfuric acid

Your contradicting youself entirely:

"Apart from that, sulfuric acid is a constituent of acid rain, which is formed by atmospheric oxidation of sulfur dioxide in the presence of water, i.e., oxidation of sulfurous acid"

wiki

just give up u lose.
 

undalay

Active Member
Joined
Dec 14, 2006
Messages
1,002
Location
Ashfield
Gender
Male
HSC
2008
1. CSU IS TOTALLY SHIT.
2. Conquering chemistry roland smith also says same shit.
(more recent and better then contexts_
3. Gas reactions can also be done in aqeuous solutions.
4. I said BOTH ways work earlier if u didnt notice.
5. SO2 + O2 has a higher activation energy then in aqeuous solution.

Gaseous oxidation is not the only way it can form.

"Some sulfuric acid is formed directly in the water droplets"
http://www.elmhurst.edu/~chm/vchembook/190acidrain.html
" The oxidation process of aqueous sulfur dioxide by molecular oxygen relies on metal catalyst such as iron and manganese. This reaction is unlike other oxidation process, which occurs by hydrogen peroxide. It requires an additional formation of an intermediate (A-), for example peroxymonosulfurous acid ion. This formation is shown below.

HSO3 H2O2 -> A- +H2O A- +H -> H2SO4
"
http://www.geocities.com/capecanaveral/hall/9111/DOC.HTML

"In the eastern United States, the primary conversion of sulfur dioxide is through an aqueous phase reaction with hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>) that exists in clouds...The result of these chemical reactions is the formation of acids in the atmosphere. These acids are, most notably, sulfuric acid (H<SUB>2</SUB>SO<SUB>4</SUN>) and nitric acid (HNO<SUB>3</SUB>). "</SUB>
<SUB>http://www.rpi.edu/dept/chem-eng/Biotech-Environ/Environmental/acidrain/acidrain.html</SUB>
<SUB></SUB>
"Sulphurous acid will oxidise to Sulphuric acid in the air[FONT=新細明體];[/FONT]or some of the sulphur dioxide (SO2) emitted will react directly with oxygen radical in the air, oxidises to sulphur trioxide SO3, then this SO3 will react with the water molecules in the air forming sulphuric acid (H2SO4)."
http://www.greeneducation.org.hk/English/focus/acid_rain_eng.htm


Oh my god u lose.
 

Tiffanys

Executed member
Joined
Aug 8, 2006
Messages
270
Location
Sydney, Australia
Gender
Female
HSC
2008
Lol chill. I really cbf to read what you wrote and I'm sure you put a lot of effort into it. Good on you. I have the revised edition of Chemistry Contexts 2007, CSU says the same, so does my school notes and my Prior notes. It's up to your interpretation I guess, either way I'm sure we'd both be marked right for this particular question.
 

YannY

Member
Joined
Aug 28, 2007
Messages
190
Gender
Male
HSC
2008
Tiffanys said:
Lol chill. I really cbf to read what you wrote and I'm sure you put a lot of effort into it. Good on you. I have the revised edition of Chemistry Contexts 2007, CSU says the same, so does my school notes and my Prior notes. It's up to your interpretation I guess, either way I'm sure we'd both be marked right for this particular question.
It says in your prior notes? shit, can i see?
 

undalay

Active Member
Joined
Dec 14, 2006
Messages
1,002
Location
Ashfield
Gender
Male
HSC
2008
ahaha yannyy i learnt everythign i know from our many debates.

edit: and yeah sorry tiffany i got a bit workked up aha
 

Tiffanys

Executed member
Joined
Aug 8, 2006
Messages
270
Location
Sydney, Australia
Gender
Female
HSC
2008
Lol tis cool, whilst not studying and bosing we've inadvertently gathered information from secondary sources about sulfuric acid and revised. =P
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top