An organic compound $A$,$C_5 H_8 O$,reacts with $H_2 O$,$NH_3$,and $CH_3 COOH$ as shown in the reaction scheme. Identify $A$.

For the given molecule, $x$, the preferred site for the attack of the electrophile is:

In the above reaction,the electrophile is substituted at the meta position only,due to:
$I$. Electron density is more at ortho $\&$ para positions
$II$. Electron density is relatively less at ortho $\&$ para positions
$III$. Electron density is less at meta position
$IV$. Electron density is relatively more at meta position
The correct answer is:

Curved arrows are used in Organic Chemistry to show the movement of electrons in the mechanism of a reaction. The correct product of the following reaction is

In the reaction,the major product formed is:

Which different types of reaction mechanisms are observed in addition reactions?