Which of the following does not contain fluorine ?

Options

A. Fluorspar
B. Cryolite
C. Fluorapatite
D. Chile salt petre

Answer

To determine which of the following compounds does not contain fluorine, we will analyze each option provided:

1. **Sodium hexafluoroaluminate**: This compound is known as a fluoride mineral and contains fluorine. The formula indicates that it has six fluorine atoms.

2. **Fluorapatite**: This is a phosphate mineral that contains fluorine in its structure. It is a form of apatite where fluorine replaces some of the hydroxyl groups.

3. **Calcium Fluoride**: As the name suggests, calcium fluoride is a compound that contains fluorine. Its chemical formula is CaF2, indicating the presence of fluorine.

4. **Child's saltpeter**: This is a mineral known as sodium nitrate (NaNO3). It does not contain any fluorine in its composition.

Now, based on the analysis of each option, we can conclude that:

**The correct answer is D. Child's saltpeter does not contain fluorine.**

### Step-by-Step Solution:
1. **Identify the compounds listed in the question.**
- Sodium hexafluoroaluminate
- Fluorapatite
- Calcium Fluoride
- Child's saltpeter

2. **Analyze each compound for the presence of fluorine.**
- Sodium hexafluoroaluminate: Contains fluorine.
- Fluorapatite: Contains fluorine.
- Calcium Fluoride: Contains fluorine.
- Child's saltpeter: Does not contain fluorine.

3. **Determine which compound does not have fluorine.**
- Based on the analysis, Child's saltpeter is the only compound that does not contain fluorine.

4. **Conclude the answer.**
- The answer to the question is D. Child's saltpeter.