Hydroboration of $1$-methylcyclopentene using $B_2D_6$,followed by treatment with alkaline hydrogen peroxide,gives

Which of the following reactions do not represent the major product of given Birch reductions?

Identify the product $B$ in the following reaction sequence:
$1,4-\text{cyclohexadiene-1,4-dicarboxylic acid}$ $\xrightarrow{NaOH} A$ $\xrightarrow{\text{Kolbe electrolysis}} B$

$A$ hydrocarbon with molecular formula $C_4H_6$ undergoes the following reactions:
$A$. Decolourises molecular bromine.
$B$. Reacts with $HBr$.
$C$. Addition of ozone and then cleavage of the ozonide by $Zn / H_2O$ gives the product $C_4H_6O_2$.
Then,the structure of the hydrocarbon is:

Which of the following most accurately describes the first step in the reaction of hydrogen chloride with $1$-butene?

When the hydrogen atom in isocyanic acid $(HNCO)$ is replaced by a methyl group,the resulting compound undergoes rearrangement to form which product?