Question

Solubitity Depends on Bond Type and Molecular Struetwre L Solubilitity and Bond Type Ionic, Non-polar Covalent, and rolar Covalent Compounds SolvemWater Substance Hexane Hexane Water Acetone Barium sulfate 3 Heptane Isopropandl Naphthalene Potassium Iodide Sodium bicarbonate Sucrose Xylene o Vegetable oil Analysis: Look at your data for heptane, naphthalene, and vegetable oil. Are they more soluble in water or in hexane? What is it about the structures of these compounds that explains this result? 1. Look at your data for KI and NaHCO3. Are they more soluble in water or in hexane? What is it about the structures of these compounds that explains this result? 2. 3. Try to explain why potassium iodide (KI) is soluble in water while barium sulfate (BaSO4) is not. Hint: Think intermolecular attraction. How do the solubilities of acetone and isopropanol compare to all of the other substances? 4. What is it about acetone and isopropanol molecules that explain this result? The solubility of many compounds can be summarized by the phrase "like dissolves like." Explain how this applies to your results. 5.

Answer 1

1. More soluble in hexane.

Reason : The solubility here is based on polarity. Polarity order is like hexane< petroleum ether < carbon tetrachloride < toluene < dichloromethane < chloroform < diethyl ether < ethyl acetate < acetone < propanol < ethanol < methanol < acetic acid < water. Hence water is the most polar and hexane is the least one. Polar compounds will dissolve in polar solvents and non-polar in non-polar solvents. This is the principle of 'like dissolves in like'. Thus heptane(non-polar) is insoluble in water and soluble in hexane. Naphthalene is also non-polar and is thus insoluble in water and soluble in hexane. Vegetable oil is also non-polar and is thus insoluble in water and soluble in hexane.

2. More soluble in water.

Both the compounds are ionic compounds and will be soluble in polar solvents. Hence are soluble in water and insoluble in hexane.

3. More the lattice energy, less the solubility. BaSO₄ has a high lattice energy and is thus insoluble in water while KI has low lattice energy. Thus KI dissolves in water.

5. Basically solubility is based on polarity. Polarity orderof commonly used solvents follow the order hexane< petroleum ether < carbon tetrachloride < toluene < dichloromethane < chloroform < diethyl ether < ethyl acetate < acetone < propanol < ethanol < methanol < acetic acid < water. Hence water is the most polar and hexane is the least one. Polar compounds will dissolve in polar solvents and non-polar compounds in non-polar solvents. This is the principle of 'like dissolves in like'i.e., polar dissolves in polar and non polar dissolves in non polar.