Which of the following alkyl-substituted alkenes is the most stable?

Surprisingly,the reaction shown below goes through a classical carbocation. What is the major product of this reaction?

In the addition of $HOBr$ to $(I)$ $Cl_3C-CH=CH_2$ and $(II)$ $CH_3-CH=CH_2$:

Which of the following reactions is correct?

Consider the given reaction. The total number of oxygen atoms present per molecule of the product $(P)$ is . . . . . .

$A$ hydrocarbon containing $2$ carbon atoms gives Sabatier and Senderen's reaction but does not give a precipitate with ammoniacal silver nitrate solution. The hydrocarbon is: