Sulphur dioxide physical properties

Substances Hazardous to Health, See also Toxic chemicals, 19, 138, 140 Substitution, 133 Sulphur, 30 Sulphur dioxide first aid, 280, 306 physical properties, 306 physiological properties, 69, 71, 304, 305 precautions, 305, 306 vapour pressure, 305 Suppression, 135 Surface area effects, 50, 199 Symbols for dangerous substances, 446, 452 Synthetic lubricants, 159 Synthetic resins, 172 Systemic poisons, 19, 77... 

Physical Properties.—Thionyl chloride is a colourless, refractive liquid, oi density 1-076 at 0° C., with freezing-point —104-5° C.s and boiling-point 79° C.,3 under atmospheric pressure. The vapour badly attacks the mucous membranes and possesses an odour recalling that of sulphur dioxide. Up to 150° C. the vapour density is normal, but above this temperature decomposition sets in, finally causing a value only two-thirds of the normal 4 (see the following). 

Physical Properties.—Sulphuryl chloride is a colourless, fuming liquid, with an extremely pungent odour. Z)2 = 1-6074 ->t " = l-4437. It boils at 69-1° C. at 760 mm. pressure, and freezes at —46° C.5 The vapour density is normal at first, but when the chloride is kept, even at 100° C., its vapour commences to dissociate into sulphur dioxide and chlorine. At 200° C. dissociation is almost complete.6 When dissolved in benzene the substance shows a molecular- weight corresponding with S02C12. At ordinary temperatures the specific heat is 0-233, the latent heat of evaporation 32-4 calories per gram, and the heat of formation from the elements approximately 89,540 calories per gram-molecule.7 The dielectric constant at 20° C. is 8-5. As a solvent, the ebullioscopic constant of sulphuryl chloride has been found to have... 

Physical Properties.—Sulphur dioxide is a colourless gas possessing a pungent, choking odour, and exerting an extremely irritating action on the mucous membrane. In consequence of this it has been used in poison gas warfare, but it is not efficient against well-equipped troops on account of the ease with which it is extracted from the air by respirators. Approximately 0-0005 per cent, can be detected by the sense of smell, whilst 0-05 j>er cent, is unendurable.2 Vegetation is injured if the concentration of the gas exceeds 0-003 per cent. 

At the point of minimum solubility of the sulphur dioxide the composition of the solvent closely approximates to that required for the monohydrate H2S04.H20 (namely 84-5 per cent, acid), and it is significant that other physical properties of the acid pass through critical values at this concentration (see p. 168). 

Physical and Chemical Properties It is a colourless liquid which boils at 153° to 156° C, with partial decomposition. On heating to 158° C., however, it decomposes into sulphuric acid, chlorine and sulphur dioxide ... 

The method for measuring pollution from sulphur dioxide must be both specific for this gas and allows its concentration measure. Its specificity depends on the presence of a physical property or a chemical reaction that detects sulphur dioxide without interference with other atmospheric constituents. The concentration measurement involves the determination of SO2 in a given volume of air, and therefore the use of an adequate instrument comprising a sampling mbe, an absorption device, a meter air and a pump. In order to track pollution changes, it is desirable that each step (measure) is carried out over a short period. However a period of 24 h is the maximum allowable. 

Table 12.16 Physical properties of carbon dioxide, sulphur dioxide, hydrogen fluoride and ammonia...

Chemical and Physical Properties of Sulphur Dioxide and Sulphur Trioxide... 

Though the data given in this chapter are available in literature, the practical application of the remarkable physical as well as chemical properties of sulphur dioxide and sulphur trioxide has been experienced and applied on large scale only recently. 

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