Question

1. X-ray films consist of a flexible plastic base coated in a gel that contains light sensitive silver halide crystals (ie., silver bromide and silver chloride). These films are exposed to X-ray radiation to produce images of the inside of a subject. Once the films are no longer needed, it is common practice to recycle the film to recover the silver. This process is done by shredding the film and placing it in a large cyanide solution bath. The silver is precipitated out as silver cyanide.

a.) What can you conclude about the water solubility of silver cyanide?

b.) Using your knowledge of limiting reactans, how can the process be optimized to ensure that the maximum amount of silver is recovered?

Answer 1

1. a) The water solubility of silver cyanide increases the solubility the solubility of silver halides (.i.e. silver bromide and silverchloride) if silver cyanide is present in sufficiently large quantity then due to formation of highly soluble complex ions it enhances the solubility where as it significantly depress solubility when present in a very small quantity, due to formation of sparingly soluble complex ions.

b) As we known limiting reactant is used up at the end of reaction but the amount of product formed in the reaction (.i.e. maximum amount of silver is recovered ) is directly proportional to the amount of limiting reactant used.

it means more the limiting reactant more will be the product formed in the reaction.