What does frequency determine for sound waves?

Hint: A wave has various parameters which define its characteristic in a medium. These parameters are wavelength, time period, wave number, wave type, frequency, etc. Frequency of a sound wave is described as the number of waves produced per second. And, mathematically it can be obtained by dividing 1 by the Time Period of the sound wave motion.

Complete answer:
Since, frequency is one of the basic characteristics of a sound wave. There must be some factor(s) that is/are affected if we change the frequency of a sound wave. The factor that is determined by frequency is known as “Pitch”.
The Pitch of a sound wave is described as the sensation of frequency. A sound wave having high frequency is said to be of higher Pitch and a sound wave of less frequency is said to have a lower Pitch.
Now, by the term sensation of frequency, we mean how that sound wave is interpreted by our ears. This can be understood with the help of an example. An Opera singer has a “thin” voice whereas a sports person has a “thick” voice. This interpretation of their voices by our ears as thin and thick is the sensation of frequency. This is because the Opera singer has a lower pitched voice whereas the sports figure has a higher pitched voice.
Hence, we can conclude that frequency determines the pitch for sound waves.

Note:
Frequency of a sound wave determines the pitch of a sound wave and not the loudness of a sound wave. Both are completely different parameters. On one hand, pitch as we saw was the highness and lowness in sound, that is, some people have a thin voice while some people have a thick voice, whereas on the other hand loudness is the measure of level of sound produced, that is, a person who is shouting is louder than a quiet person.