Question

Which of the 10 substance would you expect to be soluble in water? Which would you expect to be miscible with water? Which would you expect to be insoluble in water? Explain how you determined the solubility of each.

1. O2

2. HCl

3. Ca3(PO4)2

4. CH3CH3OH

5. SO2

6. NF3

7. C8H18

8. FeCl3

9.CH2Cl2

10. CH3NH2

Please help with 1-10 and briefly explain how you got the answer. Thank you!

Answer 1

Solubltity of compound in water depends on whether the compound is forming hydrogen bond with water molecule or not.

If Hydrogen bond is formed between the water molecules and compound added then the compound dissolve in water otherwiase doesn't dissolve.

Hydrogen forms hydrogen bond with Fluorine, Oxygen and Nitrogen.

Follow statement: "Like dissolve like" means polar compound dissolve in polar compounds only. Non-polar compound does not dissolve in polar compound.

1. O2 forms Hydrogen bond with water molecules, so it is miscible in water.

2. HCl forms hydronium ion and chloride ion when dissolve in water, so it is miscible in water.

3. It is insoluble in water because all phosphates are insoluble in water except those of sodium, potassium and ammonium due to the small size sodium, potassium and ammonium.

4. It forms hydrogen bond with water molecules, so it is miscible with water.

5. It is miscible with water because on mixing forms an acid i.e., sulfurous acid.

6. NF3 is a polar molecule and water is also polar. So it is miscible in water. This follows "Like dissolves like".

7. It is a non polar molecule, so it is not miscible in water molecule which is polar.

8. It is miscible in water and forms an acidic solution.

9. It is non polar compound so it is not miscible with water.

10. It is soluble due to presence of hydrogen bonding with water molecules.