Phenol is more acidic than:

The product of the following reaction is $P$.
$4-hydroxybenzaldehyde + PhMgBr (1 \text{ equiv.}) \xrightarrow{aq. NH_4Cl} P$
The number of hydroxyl groups present in the product $P$ is . . . . . . .

Arrange the following in increasing order of acidic character.

Which of the following phenols has the largest $pK_a$ value (i.e.,is least acidic)?

$A$ compound $A$ $(C_{7}H_{8}O)$ is insoluble in $NaHCO_{3}$ solution but dissolves in $NaOH$ and gives a characteristic colour with neutral $FeCl_{3}$ solution. When treated with bromine water,compound $A$ forms the compound $B$ with the formula $C_{7}H_{5}OBr_{3}$. $A$ is:

Among the following four compounds:
$(i)$ Phenol
$(ii)$ Methyl phenol
$(iii)$ Meta-nitrophenol
$(iv)$ Para-nitrophenol
The acidity order is: