Phenol reacts with $CHCl_3$ and $NaOH$ (at $340 \ K$) to give

$A$ trisubstituted compound '$A$',$C_{10}H_{12}O_2$ gives a neutral $FeCl_3$ test positive. Treatment of compound '$A$' with $NaOH$ and $CH_3Br$ gives $C_{11}H_{14}O_2$,with hydroiodic acid $(HI)$ gives methyl iodide,and with hot conc. $NaOH$ gives a compound $B$,$C_{10}H_{12}O_2$. Compound '$A$' also decolorises alkaline $KMnO_4$. The number of $\pi$ bonds present in the compound '$A$' is $...........$

Which of the following orders is true regarding the acidic nature of phenol and its derivatives?

$I$. $1,2$-dihydroxybenzene
$II$. $1,3$-dihydroxybenzene
$III$. $1,4$-dihydroxybenzene
$IV$. Hydroxybenzene
The increasing order of boiling points of the above-mentioned compounds is:

The action of bromine water (excess) on salicylic acid results in the formation of

An organic compound $(C_8H_{10}O_2)$ rotates plane-polarized light. It produces a pink color with a neutral $FeCl_3$ solution. What is the total number of all the possible isomers for this compound?