What kerosene fuel did the Saturn V first stage burn? The answer is RP-1. The Saturn V's S-IC first stage burned RP-1, a highly refined kerosene, together with liquid oxygen.
RP-1 was chosen because it is dense, relatively stable, and practical to store in large tanks. Those qualities mattered for the Saturn V, whose first stage carried an enormous propellant load and had to deliver powerful thrust immediately after launch. Liquid oxygen supplied the oxygen needed for combustion; RP-1 was the fuel.
The phrase “kerosene fuel” distinguishes RP-1 from the cryogenic liquid hydrogen used by the Saturn V's S-II and S-IVB upper stages. Hydrazine and Aerozine 50 were hypergolic propellants used in spacecraft and smaller propulsion systems, not the S-IC's main fuel. Boeing manufactured the S-IC stage, while Rocketdyne supplied its five F-1 engines.