Unit of enthalpy is

The correct answer is Option D: Kj/kg
Here's why:
Enthalpy is a measure of the total energy of a thermodynamic system. It's the sum of the internal energy and the product of pressure and volume.
Think of it like this: It tells you how much heat energy is contained within a substance at a given temperature and pressure, and how much energy could potentially be exchanged with the surroundings.

Now let's look at the units:
Kj (Kilojoules) is the unit for energy or heat.
kg (Kilogram) is the unit for mass.

Enthalpy is often expressed as a specific enthalpy, meaning enthalpy *per unit mass*. This is why the unit for enthalpy is Kj/kg (Kilojoules per Kilogram).

Let's examine the other options:
Option A: Kw/kg.m - Kw (Kilowatt) is a unit of power (energy per time), not energy itself, and the 'm' is for meters, a unit of length, making it unsuitable.
Option B: Kj/kg.cm - While it has Kj/kg, 'cm' (centimeter) is a unit of length and doesnt belong in enthalpy
Option C: Kw - As mentioned above, Kw (Kilowatt) is a unit of power, not enthalpy.

Therefore, Kj/kg is the correct unit for enthalpy.