Surface Chemistry - NCERT

Surface Chemistry deals with phenomena that occurat the surfaces or interfaces. The interface or surfaceis represented by separating the bulk phases by ahyphen or a slash. For example, the interface betweena solid and a gas may be represented by solid-gasor solid/gas. Due to complete miscibility, there is nointerface between the gases. The bulk phases thatwe come across in Surface Chemistry may be purecompounds or solutions. The interface is normally afew molecules thick but its area depends on the sizeof the particles of bulk phases. Many importantphenomena, noticeable amongst these beingcorrosion, electrode processes, heterogeneouscatalysis, dissolution and crystallisation occur atinterfaces. The subject of Surface Chemistry findsmany applications in industry, analytical work anddaily life accomplish Surface studies meticulously, itbecomes imperative to have a really clean very high vacuum of the order of 10 8 to 10 9pascal, it is now possible to obtain ultra clean surfaceof the metals.

silica gel, alumina gel, clay, colloids, metals in finely divided state, etc. act as good adsorbents. Adsorption in action (i) If a gas like O2, H2, CO, Cl2, NH3 or SO2 is taken in a closed vessel containing powdered charcoal, it is observed that the pressure of the gas in the enclosed vessel decreases. The gas molecules concentrate

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  Surfaces, Chemistry, Silica, Surface chemistry

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