The incorrect statement about $$B_2H_6$$ is:

Diborane ($$B_2H_6$$) has a bridged structure with two types of B-H bonds: four terminal B-H bonds and two bridging B-H-B bonds (three-centre two-electron bonds).

Let us examine each statement:

Option (2) states that the two types of B-H bonds (bridging and terminal) are not of the same length. This is correct; terminal B-H bonds are shorter (about 1.19 Å) than bridging B-H bonds (about 1.33 Å).

Option (3) states that terminal B-H bonds have less p-character compared to bridging bonds. This is correct; terminal bonds are formed using $$sp^2$$ or $$sp^3$$-like hybrid orbitals, while bridging bonds involve orbitals with higher p-character.

Option (4) states that $$BH_3$$ behaves as a Lewis acid. This is correct; $$BH_3$$ has an empty p-orbital and is electron-deficient, making it an excellent Lewis acid.

Option (1) states that all B-H-B angles are 120°. This is incorrect. The B-H-B bridge angle in diborane is approximately 97°, not 120°. The terminal H-B-H angles are close to 120° (the boron atoms are approximately $$sp^3$$ hybridized, but the terminal atoms lie in a plane), but the B-H-B bridging angles are significantly less than 120°.

Therefore, the incorrect statement about $$B_2H_6$$ is option (1).