Testing procedure of Silver by Gravimetric method

Testing Procedure of 

 SILVER (GRAVIMETRIC METHOD)

• ·     Prepare Dilute Nitric Acid (1:1 and 3:97)

•      Prepare Dilute Hydrochloric acid (1:9 v/v)

•     Weigh three nos. of 1 gm. each of sample accurately weighed up to 0.01mg

•      Transfer each sample into a 250 ml beaker. Add 15 ml of Nitric acid( 1:1)

•  Heat gently on a hot plate till the samples are completely dissolved

•      Expel all nitrous fumes

•      Remove the beakers from the hot plate

•   Dilute the content to upto 100 ml with distilled water

•      Add 20 ml of hydrochloric acid with continuous stirring

•   Cover the beakers with watch glass and put them on the hot plate. Avoid boiling

•      After 1 hour check with few drops of HCL for complete precipitation of silver

•     Keep on the hot plate for at-least  two hours (preferably overnight)

•  Remove the watch glass from the beaker while  washing with fine jet of distilled water ,wash down the walls of the beaker with distilled water and filter through sintered glass crucible using a vacuum pump

•      Wash the precipitate 2-3 times with dilute nitric acid (3 percent)  and  then 5-6 times with distilled water

•     Dry the sintered glass crucible with silver chloride precipitate in electric oven for 1 hr.

•      Cool the crucibles in a desiccator to room temperature and weigh after 1 hr. Repeat the process till constant weight is maintained.

Silver (ppt.)= Mass in g of silver chloride x 752.6

                      Mass in g of the sample