What is Baeyer's reagent?

The reaction is $2\text{-methylbuta-1,3-diene} + HBr \rightarrow \text{products}$. Identify the correct statement regarding the products of this reaction.

What is the product obtained when phenylethene is treated with $KMnO_4$ in dilute $H_2SO_4$?

The reaction of $2,3$-dichlorobutane (as shown in the image) with $Zn$ dust and heat produces an alkene. Which of the following statements is correct about the product formed?

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: Cis form of alkene is found to be more polar than the trans form.
Reason $(R)$: Dipole moment of trans isomer of $2$-butene is zero.
In the light of the above statements,choose the correct answer from the options given below:

In which case does the addition of an electrophile $NOT$ take place according to Markovnikov's rule?