part a when a ketone and its enol are in equilibrium, under most conditions the concentration of the enol is the concentration of the ketone.

Much lower than ketone is more stable than enol. N, 4-Dimethylpent -4-en-2-Amine (NH_3 protonated in acidic protoned in acidic conditions) d. [Proton cannot re extracted from OH in acidic conditions to firm O^(-)]

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.