Fractional distilation of liquid air usually produces nitrogen and oxygen as major products . Substance used to remove carbon iv oxide from air before its changed to liquid

Caustic soda

Explanation:

The fractional distillation of air is carried out on liquid air. Before air is liquified, the carbon dioxide content of air is removed using caustic soda. The air is then compressed to a pressure of about 200 atm, sudden expansion of the gas leads to cooling. The process continues until air becomes liquid at  -200°C.

Fractional distillation of liquid air usually produces nitrogen and oxygen as major products. nitrogen in obtained first since it has a lower boiling point than oxygen. The gases are then dried, compressed and stored in cylinders.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.