Final answer:
The production of radiographic film emulsion employs silver bromide (AgBr) as the radiation-sensitive chemical, which upon exposure to radiation creates the desired image on the film.
Step-by-step explanation:
The chemical used in the production of radiographic film emulsion is silver halide, specifically silver bromide (AgBr). When exposed to radiation, silver ions in the compound are reduced, creating an image on the film. This process is vital for capturing images in various types of radiography, including medical and dental X-rays.
The chemicals listed in the options provided, such as phosphorus pentachloride, dinitrogen monoxide, iodine heptafluoride, and carbon tetrachloride, are not related to the emulsion process of photographic film. For the development of the exposed film, sodium thiosulfate pentahydrate (Na2S2O3.5H2O), also known as hypo, is used as a fixer to dissolve the remaining unexposed and undeveloped silver halide crystals, thus completing the photographic process.