Bond Angle between BF3 and BH3

Bond Angle
The bond angle is the angle formed by the intersection of two bonds that share a common atom. It is measured in degrees and is determined by the repulsion between the electrons in the bonding pairs and the lone pairs of electrons.

BF3
BF3 is a trigonal planar molecule with a bond angle of 120 degrees. The central boron atom is surrounded by three fluorine atoms, which are arranged in a flat, triangular shape. The bond angle is determined by the repulsion between the bonding pairs of electrons and the lone pairs of electrons on the fluorine atoms.

BH3
BH3 is a trigonal planar molecule with a bond angle of 120 degrees. The central boron atom is surrounded by three hydrogen atoms, which are arranged in a flat, triangular shape. The bond angle is determined by the repulsion between the bonding pairs of electrons and the lone pairs of electrons on the hydrogen atoms.

Difference in Bond Angle
The bond angle in BF3 and BH3 is the same, 120 degrees. This is because both molecules have the same electron geometry, which is trigonal planar. The repulsion between the bonding pairs of electrons and the lone pairs of electrons on the surrounding atoms is the same in both molecules, leading to the same bond angle.

Conclusion
In summary, the bond angle between BF3 and BH3 is the same, 120 degrees. This is due to the similar electron geometry of both molecules, which leads to the same repulsion between the bonding pairs of electrons and the lone pairs of electrons on the surrounding atoms.