<< Chapter < Page Chapter >> Page >
Alternative spellings of sulfurous and sulfuric acids are based upon the traditional UK spelling of sulphur, i.e., sulphurous and sulphuric acid.

Sulfur dioxide and sulfurous acid solutions

The combustion of sulfur results in the formation of gaseous sulfur dioxide, [link] .

The bent structure of SO 2 is shown in [link] , and as a consequence of the sp 2 hybridization the molecule is polar.

The structure of sulfur dioxide.

The modest boiling temperature of SO 2 (-10 °C) means that it is readily liquefied and easily kept as a liquid at room temperature under a slight pressure. The liquid is associated by dipole-dipole attractions due to the polar nature of SO 2 . Liquid SO 2 is a good solvent due to the polarity of the molecule; as a consequence it readily solubalizes polar compounds and salts. It is also convenient since it is easy to remove from reaction products by evaporation.

Sulfur dioxide is soluble in water forming aqueous solutions where most of the SO 2 is maintained as a hydrogen-bonded hydrate, in a similar manner to that observed for aqueous solutions of carbon dioxide. At equilibrium in neutral water (no added base) a small fraction reacts, to give a mixture of bisulfite (HSO 3 - , [link] a) and sulfite (SO 3 2- , [link] b), [link] . The free acid does not to exist.

The structures of the (a) bisulfite, (b) sulfite, (c) disulfite, (d) dithionite, and (e) thiosulfate anions.

Bisulfite undergoes a further equilibrium, [link] , to form disulfite, whose structure is shown in [link] c.

Salts of these anions are known, and complexes of the sulfite ion are known ( [link] ), while SO 2 itself can act as a ligand to heavy metals.

The structural modes of sulfite coordination.

The bisulfite ion has strong reducing properties, e.g., [link] and [link] .

Bisulfite is also reduced by zinc in the presence of additional SO 2 , [link] , to form the highly reducing dithionite anion ( [link] d). Reaction of bisulfite with elemental sulfur yields the thiosulfate anion ( [link] e), [link] .

Sulfur trioxide and sulfuric acid

Oxidation of sulfur dioxide in the presence of a catalyst (e.g., platinum) yields sulfur trioxide, [link] , which may be condensed to a liquid at room temperature (Bp = 45 °C).

Liquid SO 3 exists as a mixture of monomer and trimers ( [link] a and b), while as a solid (Mp = 16.9 °C) it forms polymers ( [link] c).

The structure of (a) monomeric, (b) trimeric, and (c) polymeric sulfur trioxide.

The reaction of SO 3 with water results in the formation of sulfuric acid, H 2 SO 4 , as a viscous, hydrogen bonded liquid. Sulfuric acid is a strong protic acid, which in dilute solutions (in water) reacts as a dibasic acid, [link] , forming bisulfate (HSO 4 - ) and sulfate (SO 4 2- ) anions. A large number of salts are known for both anions. In addition, sulfate is known to act as a monodentate or bidentate ligand in coordination complexes.

The dissolution of SO 3 in concentrated sulfuric acid yields very corrosive, fuming sulfuric acid, which contains some pyrosulfuric acid, [link] .

Warning: The corrosive properties of sulfuric acid are accentuated by its highly exothermic reaction with water. Burns from sulfuric acid are potentially more serious than those of comparable strong acids (e.g., hydrochloric acid), as there is additional tissue damage due to dehydration and particularly secondary thermal damage due to the heat liberated by the reaction with water.

Sulfur as a source of atmospheric pollution and acid rain

Sulfur dioxide is formed as a pollutant during the combustion of sulfur containing fuels, in particular coal. While the emission of SO 2 itself leads to concerns it is its conversion to sulfuric acid in the form of acid rain that has been of concern for several decades. The pathway for the formation of sulfuric acid in the atmosphere is depandant on whether the reaction occurs in dry atmosphere or in clouds and rain.

Gaseous reactions in a dry atmosphere

In the dry atmosphere, gaseous sulfur dioxide reacts with the hydroxide radical (formed by the photochemical decomposition of ozone, [link] and [link] ) in the presence of a non-reactive gas molecule such as nitrogen, [link] . The sulfurous acid, thus formed reacts with oxygen to generate sulfur trioxide, [link] , which reacts with water to form sulfuric acid, [link] .

Measurements indicate that the conversion rate of SO 2 to H 2 SO 4 is 4% per hour on a clear sunny day, but the rate is slower during the winter.

Liquid phase reactions in clouds and rain

In the liquid phase SO 2 reacts directly with water, [link] . The bisulfite (HSO 3 - ) is oxidized by hydrogen peroxide forming a forming bisulfate (HSO 4 - ) solution, [link] .

Water soluble hydrogen peroxide is formed by the oxidation of water, [link] .

The HO 2 radical is formed by the photolysis of organic carbonyl compounds, e.g., formaldehyde in [link] and [link] .

The conversion rate is independent of pH is very fast: almost 100% per hour in summer. However, the conversion is limited by the supply of hydrogen peroxide, which is often present in much lower levels than SO 2 . Thus, a reduction in sulfur dioxide emissions does not always correlate with a reduction of wet acid deposition.

Questions & Answers

what is the meaning of function in economics
Effah Reply
Pls, I need more explanation on price Elasticity of Supply
Isaac Reply
Is the degree to the degree of responsiveness of a change in quantity supplied of goods to a change in price
Afran
Discuss the short-term and long-term balance positions of the firm in the monopoly market?
Rabindranath Reply
hey
Soumya
hi
Mitiku
how are you?
Mitiku
can you tell how can i economics honurs(BSC) in reputed college?
Soumya
through hard study and performing well than expected from you
Mitiku
what should i prepare for it?
Soumya
prepare first, in psychologically as well as potentially to sacrifice what's expected from you, when I say this I mean that you have to be ready, for every thing and to accept failure as a good and you need to change them to potential for achievement of ur goals
Mitiku
parna kya hai behencho?
Soumya
Hallo
Rabindranath
Hello, dear what's up?
Mitiku
cool
Momoh
good morning
Isaac
pls, is anyone here from Ghana?
Isaac
Hw s every one please
Afran
Ys please I'm in Ghana
Afran
what is firms
Anteyi Reply
A firm is a business entity which engages in the production of goods and aimed at making profit.
Avuwada
What is autarky in Economics.
Avuwada
what is choice
Tia Reply
So how is the perfect competition different from others
Rev Reply
what is choice
Tia
please what type of commodity is 1.Beaf 2.Suagr 3.Bread
Alfred Reply
1
Naziru
what is the difference between short run and long run?
Ukpen Reply
It just depends on how far you would like to run!!!🤣🤣🤣
Anna
meaning? You guys need not to be playing here; if you don't know a question, leave it for he that knows.
Ukpen
pls is question from which subject or which course
Ada
Is this not economics?
Ukpen
This place is meant to be for serious educational matters n not playing ground so pls let's make it a serious place.
Docky
Is there an economics expert here?
Docky
Okay and I was being serous
Anna
The short run is a period of time in which the quantity of at least one inputs is fixed...
Anna
that is the answer that I found online and in my text book
Anna
Elacisity
salihu
Meaning of economics
Suraj Reply
It will creates rooms for an effective demands.
Chinedum Reply
different between production and supply
babsnof
Hii
Suraj
hlo
eshita
What is the economic?
Suraj
Economics is a science which study human behavior as a relationship between ends and scarce means which has an alternative use.
Mr
what is supply
babsnof
what is different between demand and supply
Debless Reply
Demand refers to the quantity of products that consumers are willing to purchase at various prices per time while Supply has to do with the quantity of products suppliers are willing to supply at various prices per time. find the difference in between
Saye
Please what are the effects of rationing Effect of black market Effects of hoarding
Atty Reply
monoply is amarket structure charecrized by asingle seller and produce a unique product in the market
Cali Reply
yes
Niraj
I want to know wen does the demand curve shift to the right
Nana
demand curve shifts to the right when there's an increase in price of a substitute or increase in income
kin
ask me anything in economics, I promise to try and do justice to the question, you can send me an email or message, I will answer
kin
what are the factor that change the curve right
Nana
explain the law of supply in simple .....
freshwater
the Law of supply: states that all factor being equal, when the price of a particular goods increase the supply will also increase, as it decreases the supply will also decrease
kin
@Nana the factor that changes or shift the d demand curve to the right is 1) the increase in price of a substitute good or commodity 2) increase in income
kin
you can send your questions I am Comr. Kin chukwuebuka
kin
different between bill of exchange n treasure bill
Nana
yes
Ada
so would you tell me what means an apportunity cost plz?
Cali
what is true cost
Akiti
your question isn't correct naadi
Anthonia
define an apportunity cost?
Cali
orukpe ,is my question whats wrong or u dont know anything?
Cali
In a simple term, it is an Alternative foregone.
Sule
opportunity cost is the next best value of a scale of preference
Akiti
Both of you are not correct.
Nelly
opportunity cost: is a forgone alternative
kin
Monopoly is where is one producer produces a given product with no close substitute
James
what is income effect?
Qwecou Reply
if you borrow $5000 to buy a car at 12 percent compounded monthly to be repaid over the next 4 year what is monthly payment
Nitish Reply
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Kimberly Reply
Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
August Reply
What is the expressiin for seven less than four times the number of nickels
Leonardo Reply
How do i figure this problem out.
how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
Shanjida
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
s.
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
Researchers demonstrated that the hippocampus functions in memory processing by creating lesions in the hippocampi of rats, which resulted in ________.
Mapo Reply
The formulation of new memories is sometimes called ________, and the process of bringing up old memories is called ________.
Mapo Reply
waht is hydrating power of lithium carbonates
Mahar Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Chemistry of the main group elements. OpenStax CNX. Aug 20, 2010 Download for free at http://cnx.org/content/col11124/1.25
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Chemistry of the main group elements' conversation and receive update notifications?

Ask