What are alkenes ?

What kind of structural isomerism is shown by alkenes ?

Write IUPAC names of the following compounds:

124.

Give IUPAC names of the following compounds:
(a) CH₃CH = (CH₃)₂
(b) CH₂ = CH – C ≡ C – CH₃

Calculate the number of sigma (σ) and pi  bonds in the following structures:

Write structure and IUPAC names of different structural isomers of alkenes corresponding to C₅H₁₀. 

What is meant by hindered (or restricted) rotation around carbon-carbon double bond? What type of isomerism does it lead to?

What is geometrical isomerism? What is its cause? Give examples.

What are the necessary and sufficient conditions for a compound to exhibit geometrical isomerism ?

Name the various structural isomers possible in C₄H₈. Which one will exhibit geometrical isomerism?