Question

How many hydrogen-bonded water molecules are associated with ${\mathrm{CuSO}}_4.5{\mathrm{H}}_2\mathrm{O}$?

• A. Five
• B. One
• C. Four
• D. Three

Answer 1

The correct option is B

One

The explanation for the correct option:

Option (B):one

• In the case of ${\mathrm{CuSO}}_4.5{\mathrm{H}}_2\mathrm{O},$only four molecules of water are directly bonded or coordinated to $\mathrm{Cu}$whereas the fifth one is H-bonded to Sulfate ion.
• Here, the fifth water molecule which is hydrogen-bonded is deeply embedded in a crystal, for which It is not coordinated directly to the Cu, which can be shown as;

• Hence, only 4 water molecules are directly coordinated and one of them is hydrogen-bonded to the molecule${\mathrm{CuSO}}_4.5{\mathrm{H}}_2\mathrm{O}$.

Thus, the number of hydrogen-bonded water molecules associated with ${\mathrm{CuSO}}_4.5{\mathrm{H}}_2\mathrm{O}$ is one, option (B) is the correct answer.