Explain why solutions have a limited shelf life. Help me?

Question

Explain why solutions of good reducing agents, such as photographic developing solutions, have a limited shelf life.

Answer 1

I can't give detailed answers as the specific chemicals were not stated, but typically solutions of numerous chemicals degrade slowly over time due to a varitey of reasons. Among them are:

Exposure to light

Exposure to heat (even room temp heat)

Slow reaction with solvent (or other solutes present in solution)

Slow reaction with oxygen leaking into container.

Slow reaction with CO2 in air

Evaporation of solvent or volatile components

Also, combinations of these.

It depends on the properties of the chemical in question; some solutions are stable for decades if kept in the dark and well sealed.

Answer 2

I don't know for certain, but I'm thinking there is two possible reasons...  One is that a solution is a mixture, so then some of the compounds may "undissolve" (I forget the proper word!).  The other option is that it would be a decomposing reaction that takes place over a long period of time.

That's the best I've got, hope it helps.