Ethylene is a member of the $.....$ series.

Predict the major product $A$ for the following reaction:
$2\text{-methylbuta-1,3-diene} + HBr (1 \text{ eq.}) \xrightarrow{-80^{\circ}C (1,2\text{-addition})} A$

$A \xleftarrow[\Delta]{Cu} CH_3CH_2OH \xrightarrow[\Delta]{Al_2O_3} B$. $A$ and $B$ respectively are

Which of the following compounds will give $3, 5-$dimethyl$-6-$oxooctanal on reductive ozonolysis?

Which of the following compounds reacts with $HBr$ to form $1$-Bromo-$1$-methylcyclohexane?

What is obtained when a mixture of ethylene,carbon monoxide,and water is heated at high temperature?