Underwater, the pressure increases by 1 bar for every 10 m of depth. While a scuba diver breathes pressurized air in which the partial pressure of N2(g) exceeds 4 bar, the result is nitrogen narcosis, which is similar to alcohol intoxication. Explain what is the maximum mole percent of N2 in an air mixture that could be utilize by divers at depths up to 75 m below sea level without undue risk of nitrogen narcosis?