Molality is expressed in:

Hint: Molality: It is defined as the ratio of no. of moles of solute to that of the mass of the solvent in kg. And we know that mass is independent of temperature and so molarity.

Complete step-by-step answer:
Molality is a term that is utilized to portray the centralization of an answer. It is characterized as the number of moles of solute present in one kilogram of the solvent.
It can be written as:
${ Molality= }\frac { no.\quad of\quad moles\quad of\quad solute }{ weight\quad of\quad solvent\quad in\quad kg } $
Hence, it can be expressed as moles per kilograms or ${ mol\quad kg }^{ -1 }$.

Additional Information:
Discussing the benefits of utilizing molality as a proportion of focus is that molality, as referenced above, is exclusively reliant on the mass of solute and the dissolvable. What it implies is that these elements are not influenced by changes in temperature or even weight as on account of arrangements arranged volumetrically. Furthermore, it is very helpful in light of the fact that in an answer the molality of one solute is free of the presence of different solutes.
Going to the disadvantages, it isn't appropriate in occurrences where there is no unadulterated substance in a blend. For instance, blends, for example, water and liquor or amalgams. Here, anybody of the substance can be considered as the solvent.

Note: The possibility to make a mistake is that molality is expressed in terms of the number of moles of the solute to the weight of the solvent, not to the volume of the solution.