Which tuning fork will produce louder sound 126 Hz or256Hz?

The loudness of sound produced by a tuning fork depends on several factors, including the amplitude of the vibrations rather than just the frequency. However, in general, human perception of loudness is more sensitive to higher frequencies. Thus, while the 256 Hz tuning fork may be perceived as louder to the average human ear, the actual loudness will depend on the specific design and construction of the Tuning Forks.