Answer:
10 Atoms
Step-by-step explanation:
The structure of said compound is sketched according to guide lines provided in statement and is attached below.
Hydrogen Bond Interactions:
Hydrogen Bond Interactions are those interactions which are formed between a partial positive hydrogen atom bonded directly to most electronegative atom (i.e. F, O and N) of one molecule and the partial negative most electronegative atom of another molecule.
In given structure we are having seven most electronegative oxygen atoms (labelled red) and three partial positive hydrogen atoms (labelled blue) directly attached to most electronegative atom (i.e. oxygen atoms).
Therefore, the oxygen atoms will make hydrogen bonds with water's hydrogen atoms and the partial positive hydrogen atoms will make hydrogen bonds with water's oxygen atoms respectively.