I have 2 chemicals, A & B. Note: both do not contain buffer salts.

Chemical A expires 1 week later.
Chemical B expires next year.
I prepare solution C (general laboratory reagent)containing Chemicals A & B.
When assigning the expiry date of solution C, does this mean the expiry date should not exceed 1 week because Chemical A expires l week later?

Please help. Thanks.

My personal opinion is that you don't know. Part of the answer depends upon how chemical A decomposes and part depends upon the makeup of chemical C.

When preparing solution C, the expiry date should be determined based on the chemical with the shortest expiry date, which in this case is Chemical A that expires in 1 week. This means that the expiry date of solution C should not exceed 1 week, as the effectiveness of Chemical A will deteriorate after that time.

To clarify this concept, it's important to understand that the expiry date of a solution is determined by the least stable component. In this case, Chemical A has a shorter shelf life compared to Chemical B. If the expiry date of solution C was determined by Chemical B, it would be much longer than 1 week, potentially up to a year.

To calculate the expiry date of solution C, you would need to consider the expiry date of Chemical A and ensure that the solution is used before Chemical A expires. The stability of Chemical B should also be taken into account, but it is not the governing factor in determining the expiry date of the solution.

It is important to note that solutions are generally expected to have a shorter shelf life compared to individual chemicals, as the interaction between the components in the solution may cause faster degradation or chemical reactions. Therefore, it is recommended to use the solution within the shortest expiry date of the individual components.