H2SO4, fuming

Hot H2SO4, fuming HNO3, HCIO4, hydroxyl radicals (H2O2 and Fe(NH4)2(S04)2)... 

H2SO4 (oleum) (over 98% H2SO4) Fuming Corrodes at all temperatures... 

Stong oxidizing agents (KMNO4, H2SO4, fuming HNOa, NaNOj, etc )... 

Reagents cone. H2SO4, fuming HNO3, methanol, ice. 

Transfer 1.000 g Nb (or 1.4305 g Nb20g) to Pt dish, add 20 ml HP, and heat gently to complete dissolution. Cool, add 40 ml H2SO4, and evaporate to fumes of SO3. Cool and dilute to volume with 8 M H2SO4. 

Phenol sulfonic acid (determination of nitrogen as nitrate water analysis for nitrate) dissolve 25 g pure, white phenol in 150 mL of pure concentrated H2SO4, add 75 mL of fuming H2SO4 (15% SO3), stir well and heat for two hours at 100°C. 

Acid pickling This can be done under the following operating conditions, either with sulphuric acid (H2SO4), or hydrochloric acid (HCl). H2SO4 releases a lot of fumes and is ineffective under cold conditions. It forms iron sulphate, which forms a hard deposit at the bottom of the tank and is difficult to remove (see table on next page). 

Dissolved in 20% NaOH, extracted with a small amount of C6H6, then steam distd, until clear. The soln was then cooled and acidified slightly with 15% H2SO4. The thiol was distd out, dried with CaS04 or CaCl2, and fractionally distd under N2 [Mathias and Filho J Phys Chem 62 1427 1958]. Also purified by pptn as lead mercaptide from alcoholic soln, with regeneration by adding dilute HCl to the residue after steam distn. All operations should be carried out in a fume cupboard due to the TOXICITY and obnoxious odour of the thiol. 

Paraffin (oil) [8012-95-1 ] d 0.880, n 1.482. Treated with fuming H2SO4, then washed with water and dilute aqueous NaOH, then percolated through activated silica gel. 

Trichlorobenzene [120-82-1] M 181.5, m 17 , b 210 . Separated from a mixture of isomers by washing with fuming H2SO4, then water, drying with CaS04 and slowly fractionally distilling. [Jensen, Marino and Brown J Am Chem Soc 81 3303 7959.]... 

Arsenic III oxide (arsenic trioxide, arsenious oxide) [1327-53-3] M 197.8, three forms m 200°(amorphous glass), m 275°(sealed tube, octahedral, common form, sublimes > 125° without fusion but melts under pressure), m 312°, pKj 9.27, pK 13.54, pK 13.99 (for H3ASO3). Crystd in octahedral form from H2O or from dil HCl (1 2), washed, dried and sublimed (193°/760mm). Analytical reagent grade material is suitable for use as an analytical standard after it has been dried by heating at 105° for l-2h or has been left in a desiccator for several hours over cone H2SO4. POISONOUS (particulary the vapour, handle in a ventilated fume cupboard). 

Hydrogen chloride [7647-01-0] M 36.5. Passed through cone H2SO4, then over activated charcoal and silica gel. Fumes in moist air. Hydrogen chloride in gas cylinder include ethylene, 1,1-dichloroethane and ethyl chloride. The latter two may be removed by fractionating the HCl through a trap cooled to -112°. Ethylene is difficult to remove. Fumes in moist air. HARMFUL VAPOURS. 

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