Laboratory Report on Gravimetric Determination of Chloride Paper

Laboratory Report on Gravimetric Determination of Chloride Paper

Introduction of gravimetric determination of chloride

Laboratory Report on Gravimetric Determination of Chloride: The use of silver nitrate to form the precipitate of silver chloride and gravimetrically determine the amount of chloride present in the sample is one of the most common methods employed in lab. Any inorganic compound containing halogen can be made into aqueous solution and treated by silver nitrate to obtain the precipitates of silver halide. The reaction involved is as follows:Laboratory Report on Gravimetric Determination of Chloride Paper

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Ag+ + X− (aq) → AgX (precipitate)

where X− = Cl−, Br−, or I−.

Laboratory Report on Gravimetric Determination of Chloride NB: This essay is a result of a test that we gave our recruits. If we want our professional writers to handle your assignment, kindly ORDER NOW below.Laboratory Report on Gravimetric Determination of Chloride Paper

In this lab, chloride salt was used as test sample. The salts (both known and unknown) were treated with silver nitrate to obtain white precipitates of silver chloride. The silver chloride was initially formed as colloidal solution. After subsequent heating, nucleation process was dominated by particle growth and the precipitates separated out as coagulated mass.Laboratory Report on Gravimetric Determination of Chloride Paper

During this procedure, the pH of the solution is kept slightly acidic by addition of Nitric acid. The acidic pH eliminates the interference by anions (like carbonate and sulphides) of weak acid (www.wikipedia.org). Otherwise, these anions can from sparingly soluble silver salt in neutral pH. Similarly, the silver nitrate is also added in a little excess to enhance the formation and diminish the solubility of silver chloride (Le Chatelier’s Principle). Moreover, the combined action of moderately high pH and slightly excess silver nitrate promotes the coagulation of the silver chloride precipitate by formation of dielectric layer (Skoog, 317-319).Laboratory Report on Gravimetric Determination of Chloride Paper

During the experiment, if the precipitate of silver chloride is exposed to light, it photo-decomposes to give elemental silver and chlorine gas. The elemental silver (violet color seen in precipitate) combines with other chloride ion to from silver chloride.

 

However, due to the chloride that escaped as gas, the product is lost and that gives low yield (www.cooper.edu). Although, in practice, the amount of silver chloride nitrate that decomposed is negligible, it is better to avoid exposure to direct light. The photodecomposition formula is as follows:Laboratory Report on Gravimetric Determination of Chloride Paper

However, due to the chloride that escaped as gas, the product is lost and that gives low yield (www.cooper.edu). Although, in practice, the amount of silver chloride nitrate that decomposed is negligible, it is better to avoid exposure to direct light. The photodecomposition formula is as follows:Laboratory Report on Gravimetric Determination of Chloride Paper

2 AgCl (s) → 2 Ag (s) + Cl2 (g)

3 C12 (aq) + 3 H2O (l) + 5 Ag+ (aq) → 5 AgCl (s) + C1O3-(aq) + 6 H+(aq) Laboratory Report on Gravimetric Determination of Chloride Paper