What are the suitable conditions for the following transformation?

Assertion : $trans-but-2-ene$ on reaction with bromine forms a racemic mixture.
Reason : $trans-$Compound in $trans$ addition forms two types of stereoisomers.

Identify the major product of the following reaction:

Write $IUPAC$ names of the products obtained by the ozonolysis of the following compounds:
$(i)$ $Pent-2-ene$
$(ii)$ $3,4-Dimethylhept-3-ene$
$(iii)$ $2-Ethylbut-1-ene$
$(iv)$ $1-Phenylbut-1-ene$

In the following reaction: $CH_3-C(CH_3)_2-CH=CH_2 \xrightarrow{H_2O/H^{+}} A + B$,the major product is:

When ethanol is heated with conc. $H_{2}SO_{4}$,a gas is produced. The compound formed,when this gas is treated with cold dilute aqueous solution of Baeyer's reagent,is: