The purity of an organic compound is determined by

Options

A. Density
B. Melting point
C. Mixed melting point
D. Molecular mass

Answer

To determine the purity of an organic compound, we can follow these steps:

### Step 1: Understand the Characteristics of Pure Substances
Pure organic compounds have specific physical properties, such as a definite melting point, boiling point, and refractive index. These properties are consistent and do not vary.

**Hint:** Remember that pure substances have fixed physical properties that can be used for identification.

### Step 2: Identify the Method for Determining Purity
Among the options given (density, melting point, mixed melting point, molecular mass), we need to focus on methods that can indicate purity. The melting point is a crucial characteristic of a pure substance.

**Hint:** Consider which property is most sensitive to impurities in a substance.

### Step 3: Analyze the Effect of Impurities
When an organic compound is impure, its melting point will not be sharp. Instead, it will be depressed and may range over a wider temperature interval. This means that the melting point of an impure substance is not a single value but rather a range.

**Hint:** Think about how impurities affect the physical properties of a substance.

### Step 4: Conclude the Best Method for Purity Determination
Since the question asks for the method to determine the purity of an organic compound and given the options, the melting point is the most appropriate choice. It is a direct indicator of purity, as pure substances have a specific melting point.

**Hint:** Recall that melting point is often used in laboratories to assess the purity of organic compounds.

### Final Answer
The purity of an organic compound is determined by the **melting point**.