Final answer:
In chronic granulomatous disease, the impaired neutrophilic function is the production of superoxide radicals due to defects in the NADPH oxidase system, leading to reduced antibacterial activity of phagocytes.
Step-by-step explanation:
The neutrophilic function that is impaired in chronic granulomatous disease (CGD) is the ability of phagocytic cells, like neutrophils, to produce superoxide radicals.
In CGD there are defects in the NADPH oxidase system of these cells which prevent the production of superoxide radicals in phagolysosomes a critical component in the antibacterial activity of phagocytes. This impairment leads to a reduced ability to combat bacterial infections resulting in persistent infections and the formation of chronic granulomas.