Compound S, an isomer of C_{4}*H_{8}*C*l_{2} produces a proton n.m.r. spectrum which 34 consists only of a singlet, a triplet and a quartet with an integration ratio of 3:3:2 respectively. Compound ?

The compound that fits this description is 1-chloro-2-methylbutane (CH3CHClCH2CH3).

Compound S:

- Molecular formula: C₄H₈Cl₂
- Proton NMR spectrum:
- Singlet (3H)
- Triplet (3H)
- Quartet (2H)

Structural Analysis:

Based on the NMR spectrum, compound S must have the following features:

- One methyl group (3H singlet)
- One methylene group with two equivalent hydrogens (3H triplet)
- One methylene group with one hydrogen adjacent to the carbon bearing the chlorine atoms (2H quartet)

The only isomer of C₄H₈Cl₂ that satisfies these features is:

1,1-Dichloroethane

Structure:

```
Cl-CH₂-CH₂-Cl
```

Proton NMR Spectrum:

- Singlet (3H): Methyl group (CH₃)
- Triplet (3H): Methylene group (CH₂ adjacent to CH₃)
- Quartet (2H): Methylene group (CH₂ adjacent to Cl)

The integration ratios match the observed 3:3:2 ratio in the NMR spectrum.