$X$ in the above reaction is

The major product of the following reaction is $F_3C-CH=CH_2 + HBr \rightarrow$

Rank the following alkenes in order of increasing $\lambda_{max}$:
$(1)$ $A$ conjugated diene in a bicyclic system.
$(2)$ An isolated diene in a bicyclic system.
$(3)$ $A$ conjugated diene in a bicyclic system (different substitution pattern).

What is the structure of the $2$-butenyl radical?

Write the structures and $IUPAC$ names of the different structural isomers of alkenes corresponding to the molecular formula $C_5H_{10}$. How many such isomers are possible?

Name the alkene with molecular formula $C_{10}H_{20}$.