100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.
INDETIFY AS ELEMENT COMPOUND OR MIXTURE SULFER DIOXIDE HOW TO
COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.From tech to household and wellness products. This Time in History In these videos, find out what happened this month (or any month!) in history.#WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.Demystified Videos In Demystified, Britannica has all the answers to your burning questions.Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.Na 2S 2O 3 ( aq) + 2 HCl ( aq) NaCl ( aq) + H 2O ( l) + S ( s) + SO 2 ( g)įor those who are anxious about the spelling of sulfur click here. GCSE students of Chemistry often come across another way to produce sulphur dioxide in their study of reaction rates in the " disappearing cross" experiment (link slow to load). NaHSO 3 ( aq) + H 2SO 4 ( aq) NaHSO 4 ( aq) + H 2O ( l) + SO 2 ( g) Sulphur dioxide also finds uses as in bleaching and in purifying petroleum products.Īdditional ways to produce sulphur dioxide are to drip concentrated sulphuric acid onto a concentrated solution of sodium hydrogen sulphite. Sulphur dioxide is found in soft drinks such as fruit juices, some meats and wines. Next time you go to a supermarket why not check food labels to see if they contain sulphur dioxide (additives E220 and E221) or a chemical, which decomposes to produce the gas ( E222-8). Increasingly there are health concerns with sulphur dioxide as it can trigger asthma in certain individuals. The main human sources of sulphur dioxide are burning fossil fuels, smelting, paper manufacture and the production of sulphuric acid via the Contact Process. The main natural sources of sulphur dioxide are volcanoes, forest fires and oceans. It has found use as an antioxidant, which can help prevent food from spoiling. As the oxidation number of chromium is reduced from 6+ to 3+ this clearly indicates a useful property of sulphur dioxide, namely it is a reducing agent. The paper goes from an orange colour for the Cr 6+ to a green colour for Cr 3+. Sulphur dioxide exists as individual covalent V-shaped planar molecules with an OSO bond angle of 120°Ī simple test for sulphur dioxide is to pass the gas over a piece of filter paper soaked in acidified Na 2Cr 2O 7. Statistics are available on sulphur dioxide levels from 1974 to 1998. Much has now been done to reduce SO 2 emissions with desulphurisation of fuels to help reduce acid rain. This is possible as UV radiation in the upper atmosphere catalyses the reaction between sulphur dioxide and oxygen to produce sulphur trioxide which goes on to react with water. Sulphur dioxide is a major component of acid rain since it mixes with water vapour in the atmosphere, reacting to produce sulphuric acid ( H 2SO 4). The resulting acid is the weakly dibasic acid sulphurous acid (H 2SO 3). Sulphur dioxide is an acidic gas and this can easily be demonstrated by adding water and a few drops of universal indicator to a container of the gas. This looks quite impressive in a darkened room.Īn alternative laboratory preparation is to heat copper turnings with concentrated sulphuric acid (H 2SO 4), see image, right.Ĭu ( s) + 2 H 2SO 4 ( aq) CuSO 4 ( aq) + SO 2 ( g) + 2 H 2O ( l) Burning molten sulphur in either air or pure oxygen leads to a reaction, which produces a pale blue coloured flame. Sulphur dioxide gas can be made directly by heating its constituent elements. It has a melting point of -72.7☌, and a boiling point of -10☌. Sulphur dioxide is a dense colourless gas, which is soluble in water, and has a suffocating and unpleasant smell of burnt matches. Sulphur forms two main oxides the gas sulphur dioxide (SO 2) and the liquid sulphur trioxide (SO 3). Also available: HTML, JMol, and VRML versions.