A molecule, C4H9Cl, is analysed - HSC - SSCE Chemistry - Question 14 - 2019 - Paper 1

To determine the structural formula of the given molecule C4H9Cl, we shall analyze the NMR spectrum and the molecular formula.

1. Analyze the NMR Spectrum: The spectrum shows a prominent peak, which indicates that there are likely protons in different environments. The integration of peaks indicates the number of hydrogen atoms.

2. Count Carbons and Hydrogens: The molecular formula C4H9Cl suggests that the molecule contains a total of four carbon atoms, nine hydrogen atoms, and one chlorine atom.

3. Evaluate the Structures Provided:

   • Option A: This structure is CH3-C-Cl-CH3. However, this results in C4H8Cl, which does not match.
   • Option B: This is CH3-CH-CH2-Cl with a tertiary carbon. This would give a different formula and more chlorine substitutions.
   • Option C: This shows CH3-CH2-CH2-Cl that gives C4H9Cl, thus matching.
   • Option D: This structure is CH3-CH2-CH2-CH2-Cl, resulting in C5H11Cl, which is incorrect.

4. Conclusion: Option C gives a structural formula that aligns perfectly with C4H9Cl. Therefore, the answer is:

C: CH3 – CH2 – CH2 – Cl.