But-2-ene on reaction with alkaline KMnO₄ at elevated temperature followed by acidification will give :

The mole fraction of a solvent in aqueous solution of a solute is 0.8. The molality (in mol kg^–1 ) of the aqueous solution is :

The electrons are more likely to be found :

An organic compound 'A' is oxidizod with Na₂O₂ followed by boiling with HNO₃. The resultant solution is then treated with ammonium molybdate to yield a yellow precipitate.
Based on above observation, the element present in the given compound is: