[rhyno-of-the-port]

Hello, i've synthesised 9-fluorenone-4-carboxylic acid and now need to explain the reaction with sulfuric acid and why it turns yellow?
I also need to explain why, when i do a di-nitration to it, the nitro groups orientate themselves at positions 2 and 7?
I will be very greatful to anyone who can help me

[sanderol]

the positioning of the nitrogroup depents on the directioning of the substituents. In this case the Acid group and the keto group are both meta directing so this gives makes the 2-7 position reactive.