Van't Hoff factors of aqueous solutions of `X,Y,Z` are `1.8,0.8 "and" 2.5`. Hence, their (assume equal concentrations in all three cases)

Options

A. `b.p.:XltYltZ`
B. `f.p.ZltXltY`
C. osmotic pressure `:X=Y=Z`
D. `v.p .: YltXltZ`

Explanation

To solve the problem regarding the Van't Hoff factors of aqueous solutions of substances X, Y, and Z, we will analyze the effects of these factors on boiling point elevation, freezing point depression, osmotic pressure, and vapor pressure.

### Step-by-Step Solution:

1. **Identify the Van't Hoff Factors**:
- For substance X, \( i_X = 1.8 \)
- For substance Y, \( i_Y = 0.8 \)
- For substance Z, \( i_Z = 2.5 \)
...