For compound having the formula GaAlCl4, the correct option from the following is:

1. Structural Composition: The compound $GaAlCl_4$ is an ionic salt rather than a covalent molecule. It is correctly formulated as:$[Ga]^+ [AlCl_4]^-$ Cation: Gallium exists in the $+1$ oxidation state ($Ga^+$). This is a result of the Inert Pair Effect, where the $4s^2$ electrons remain unshared due to poor shielding by the $3d^{10}$ electrons.

Anion: Aluminum is the central atom in the tetrahedral complex anion $[AlCl_4]^-$, where it exists in its stable $+3$ oxidation state.

2. Electronegativity Anomaly In Group 13, electronegativity does not follow a perfectly descending trend. Due to the d-block contraction (Transition Contraction), the effective nuclear charge ($Z_{eff}$) of Gallium is higher than that of Aluminum. Gallium follows the $3d^{10}$ series, and the poor shielding of $d$-electrons causes the nucleus to hold the valence electrons more tightly.

The Pauling electronegativity values are: \text{Electronegativity of Al } (\chi_{Al}) \approx 1.51$$\text{Electronegativity of Ga } (\chi_{Ga}) \approx 1.6.

Evaluation of Options: Option A: Incorrect. $Ga^+$ is an isolated cation in the lattice; it is not the central coordinating atom for the $Cl$ ligands.

Option B: Correct. As shown above, $Ga$ is more electronegative than $Al$ and acts as the cation ($Ga^+$).

Option C: Incorrect. $Cl$ is covalently bonded to $Al$ within the $[AlCl_4]^-$ unit. The interaction between $Ga^+$ and $Cl^-$ is predominantly ionic.

Option D: Incorrect. The oxidation state of Gallium in this specific compound is $+1$.