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On a laboratory scale, sulfuric acid can be diluted by pouring concentrated acid onto crushed ice made from de-ionized water. The ice melts in an endothermic process while dissolving the acid. The amount of heat needed to melt the ice in this process is greater than the amount of heat evolved by dissolving the acid so the solution remains cold.
Corrosion may occur where stale sewage generates hydrogen sulfide gas into an atmosphere containing oxygen gas and high relative humidity. There must be an underlying anaerobic aquatic habitat containing sulfates and an overlying aerobic aquatic habitat separated by a gas phase containing both oxygen and hydrogen sulfide at concentrations in excess of 2 ppm.
Anhydrous nitric acid, referred to as white fuming nitric acid, can be used to prepare water-free nitration mixtures, and this method is used in laboratory scale operations where the cost of material is not of primary importance. Fuming nitric acid is hazardous to handle and transport, because it is extremely corrosive and volatile.
The first and faster [citation needed] process is the removal of hydrogen and oxygen as units of water by the concentrated sulfuric acid. This occurs because hydration of concentrated sulfuric acid is strongly thermodynamically favorable, with a standard enthalpy of reaction ( ΔH ) of −880 k J / mol .
This group is determined by adding the salt in water and then adding dilute hydrochloric acid (to make the medium acidic) followed by hydrogen sulfide gas. Usually it is done by passing hydrogen sulfide over the test tube for detection of 1st group cations. If it forms a reddish-brown or black precipitate then Bi 3+, Cu 2+, Hg 2+ or Pb 2+ is ...
The sodium fusion extract is made alkaline by adding NaOH.To this mixture, freshly prepared FeSO 4 solution is added and boiled for some time and then cooled. A few drops of FeCl 3 are added and Prussian blue (bluish green) color forms due to formation of ferric ferrocyanide along with NaCl.
in the condensation of the water-vapour of the air on the cold surface of a glass; in the capillarity of hair, wool, cotton, wood shavings, etc.; in the imbibition of water from the air by gelatine; in the deliquescence of common salt; in the absorption of water from the air by concentrated sulphuric acid; in the behaviour of quicklime". [4]
Sulfamic acid is preferable to hydrochloric acid in household use, due to its intrinsic safety. If inadvertently mixed with hypochlorite based products such as bleach , it does not form chlorine gas, whereas the most common acids would; the reaction ( neutralisation ) with ammonia , produces a salt, as depicted in the section above.