[Qweetryy]

Hi, as a part of my of a preparation for an Olympiad I decided to do something more than solving theoretical problems in books. When it comes to making my own lab at home and buying the reagents – what are the safe concentrations e.g. for HCl, H2SO4? Is it safe to use 25% NH3(aq) without fume hood?

[Arkcon]

Hi there, Qweetryy:.  You might want to review our Citizen Chemist sub-forum.  There's no shortage of tips for the home chemist on that sub-forum.

How practical home lab chemistry, or playing around with possibly dangerous reagents, will in any way help you with the theoretical examination, is what I don't see.  And while the practical examination may call for procedures to be performed, reviewing an example online leads me to believe you'd be better off practicing using glassware at school, even just measuring water repeatedly to determine how to improve your technique for accuracy and reproducibility.