[NsgyDoc]

I am helping my daughter to grow some crystals, utilizing NaCl and various solvents.  In the H2O2 solution, we have salt crystalized, but also a yellow amorphous looking substance/crystal attached to the string in the solution.  I am aware that some O2 was released as a result of the initial conversion of H2O2 to H20 and O2, and presumed that perhaps some NaOH may be produced.  What is the other yellow substance crystallizing out of the solution?

I should add, as I've thought further, she has a brass-colored paper clip weighting down a string in the solution.  Assuming that this may actually contain some brass, any thoughts on whether the yellow substance may be a reaction with the copper (or zinc), and if so, what would be the most likely compound?  The yellow suggests some contaminant, as I haven't been able to explain it on the basis of just NaCl, H2O2, and H20.

[nj_bartel]

What color is the solution?  What concentration is the peroxide?

[AWK]

H₂O₂ oxidizes many metals including copper. Use thread instead of string