Arrange the following set of compounds in order of their decreasing relative reactivity with an electrophile, `E^(+)`.
(i) chlorobenzene, `2, 4-`dinitrochlorobenzene, `p-`nitrochloro benzene
(ii) toluene, `p-H_(3)C-C_(6)H_(4)-CH_(3),p-H_(3)C-C_(6)H_(4)-NO_(2),p-O_(2)N-C_(6)H_(4)-NO_(2)`

Explanation

To arrange the given compounds in order of their decreasing relative reactivity with an electrophile, we need to analyze the electron density on the benzene rings of each compound. The more electron-rich a compound is, the more reactive it will be towards an electrophile, as electrophiles seek areas of high electron density.

### Part (i): Compounds - Chlorobenzene, 2,4-Dinitrochlorobenzene, p-Nitrochlorobenzene

1. **Chlorobenzene**:
- Chlorine (Cl) is a weakly electron-withdrawing group due to its electronegativity, but it also has a +M (mesomeric) effect which can donate some electron density to the ring. Thus, chlorobenzene has a moderate electron density.

2. **2,4-Dinitrochlorobenzene**:
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