The final product formed by the ozonolysis of compound $RCH=CR_2$ is

Lactic acid on heating with conc. $H_2SO_4$ gives

Which among the following alkenes is most stable?

The major product of the above reaction is

The metal used for the de-bromination reaction of $1, 2$-dibromoethane is:

In the reaction with $HCl$,an alkene reacts in accordance with Markovnikov's rule to give the product $1-$chloro$-1-$methylcyclohexane. The possible alkene is: