When isomers have the same structural formula but differ in the relative arrangement of atoms or groups,they are called ........

Find out the statements which are not true.
$A$. Resonating structure with more number of covalent bonds and lesser charge separation are more stable.
$B$. In electromeric effect,an unsaturated system shows $+E$ effect with nucleophile and $-E$ effect with electrophile.
$C$. Inductive effect is responsible for high melting point,boiling point and dipole moment of polar compounds.
$D$. The greater the number of alkyl groups attached to the doubly bonded carbon atoms,higher is the heat of hydrogenation.
$E$. Stability of carbanion increases with the increase in $s$-character of the carbon carrying the negative charge.
Choose the correct answer from the options given below.

The product of this reaction should be

How many stereoisomers does this molecule have?
$CH_3CH=CHCH_2CH(Br)CH_3$

How many isomers (cyclic and acyclic) are possible for a compound with molecular formula $C_3H_6O$?

Identify the total number of compounds containing at least one chiral carbon atom from the following list:
$1$. $2-$methylcyclohexanone
$2$. Cyclopentane$-1,3-$dione
$3$. $CH_3-CH_2-CH(NO_2)-COOH$
$4$. $CH_3-CH(I)-CH_2-NO_2$
$5$. $CH_3-CH_2-CH(OH)-CH_2OH$
$6$. $CH_3-CH_2-CH(I)-C_2H_5$