Geminal diols (compounds with two $-OH$ groups on the same carbon atom) are generally unstable. However,which of the following is stable?

Compound $P$ $(C_{8}H_{8}O)$ gives a red-orange precipitate with $2,4-DNP$ reagent and it does not reduce Fehling's reagent. On drastic oxidation with chromic acid, $P$ gives an aromatic product $Q$ that produces effervescence on treating with aqueous $NaHCO_{3}$. Compound $P$ and $Q$, respectively, are:

Write about $(a)$ Tollen's Test and $(b)$ Fehling solution. $OR$ Write the oxidation reaction of only aldehyde. $OR$ Write tests which are utilized to differentiate aldehydes and ketones.

Which of the following does not give an aldol reaction with dil. $NaOH$?

Which of the following does not give a yellow precipitate with $NaOH + I_2$?

Which is the major product of the following reaction?