If the heat of hydrogenation of $1$-butene is $30 \ kcal$,what is the heat of hydrogenation of $1,3$-butadiene (in $kcal$)?

The product $(C)$ of the reaction is:

The decreasing order of heat evolved upon catalytic hydrogenation of the given reactants with $H_2\ (Pd/C)$ is:

Write the main product of the given reactions:
$(1)$ $C_6H_5CH = CH_2 \xrightarrow{HBr}$
$(2)$ $C_4H_{10} \xrightarrow{\text{air}, \Delta}$

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

Arrange the following in the correct order of their acidic strength:

$I. H_2C=CH_2$

$II. CH \equiv CH$

$III. CH_3-C \equiv CH$

$IV. CH_3-CH_3$