The conversion of $O$-acylated phenol to $C$-acylated phenol in the presence of $AlCl_3$ is an example of which type of organic reaction?

If $\int_{-1}^{4} f(x) \, dx = 4$ and $\int_{2}^{4} (3 - f(x)) \, dx = 7$,then the value of $\int_{2}^{-1} f(x) \, dx$ is

The element with atomic number $12$ belongs to ......... group and ......... period.

Bromine is commercially prepared from sea water by displacement reaction:
$Cl_2 + 2Br^{-}_{(aq)} \to 2Cl^{-}_{(aq)} + Br_2$
$Br_2$ gas thus formed is dissolved into a solution of $Na_2CO_3$ and then pure $Br_2$ is obtained by treatment of the solution with:

If $ab \neq 0$ and the sum of the coefficients of $x^7$ and $x^4$ in the expansion of $\left(\frac{x^2}{a}-\frac{b}{x}\right)^{11}$ is $0$,then

Plaster of Paris,when mixed with the correct amount of water,sets into a solid mass due to the formation of: