What is diels alder conjugate base 4,2 and 2,2 reaction and how the light promote the orbital in alpha, beta unsaturated ketone?

To prevent the presence of air, noble gases are placed over highly reactive chemicals to act as inert "blanketing" gases. a chemical engineer places a mixture of noble gases consisting of 4.37 g of he, 13.36 g of ne, and 36.65 g of kr in a piston-cylinder assembly at stp. calculate the partial pressure in torr of kr.