Physical Properties 2-methylcyclohexanol 4-methylcyclohexanol 1-methylcyclohexene 3-methylcyclohexene 4-methylcyclohexene Phosphoric acid (85% in water) Molecular Weight Boiling Point (°C) Density (g/mL) (g/mole) 114.2 166 0.930 114.2 173 0.914 96.2 110 0.813 96.2 104 0.801 96.2 102 0.799 98.0 n/a 1.7
The Correct Answer and Explanation is:
Correct Interpretation of the Data Table
The table titled “Table 1. Physical Properties” presents the molecular weight, boiling point, and density of various organic compounds and a reagent. Below is a summary of the important points and comparisons:
Boiling Point Comparison (in °C):
- Highest: 4-methylcyclohexanol (173°C)
- 2nd: 2-methylcyclohexanol (166°C)
- 3rd: 1-methylcyclohexene (110°C)
- 4th: 3-methylcyclohexene (104°C)
- Lowest: 4-methylcyclohexene (102°C)
- Phosphoric acid is listed as “n/a” because its boiling point is not provided.
Density Comparison (in g/mL):
- Highest: Phosphoric acid (85% in water): 1.70 g/mL
- 2nd: 2-methylcyclohexanol: 0.930 g/mL
- 3rd: 4-methylcyclohexanol: 0.914 g/mL
- 4th: 1-methylcyclohexene: 0.813 g/mL
- 5th: 3-methylcyclohexene: 0.801 g/mL
- Lowest: 4-methylcyclohexene: 0.799 g/mL
Molecular Weight (in g/mol):
- The alcohols (2-methylcyclohexanol and 4-methylcyclohexanol) each have a molecular weight of 114.2 g/mol.
- All methylcyclohexenes (1-, 3-, and 4-) have the same molecular weight of 96.2 g/mol.
- Phosphoric acid (85% aqueous) has a molecular weight of 98.0 g/mol.
Explanation:
The data show that the methylcyclohexanol compounds (alcohols) have higher molecular weights and higher boiling points than the corresponding methylcyclohexenes (alkenes). This difference is due to the presence of the hydroxyl group in alcohols, which allows hydrogen bonding, increasing intermolecular attractions and leading to higher boiling points.
Among the alkenes, the small variations in boiling point and density are likely due to structural differences in the position of the methyl group. Phosphoric acid, being a strong acid in water, has a much higher density due to its ionic and polar nature. This table is useful for predicting physical behavior in separation or reaction setups, such as distillation.
