We are studying the chalcogens at school. I should prove (show) the acid nature of $\ce{H2S}$ by writing two chemical interactions. I am really sorry if the terms I am using aren't the right ones. It's the first time I've ever used this part of the language. Which reactions should I write, and w...

I am doing some research regarding carotenoids and beta-carotene. After extracting the sample, I have not been able to find a way to measure antioxidant activity of beta-carotene. I have $\pu{0.1mM}$ of DPPH (2,2-diphenyl-1-picrylhydrazyl) solution dissolved in methanol, but I just read that you ...