When BCl 3 gas is passed through an electric discharge, small amounts of the reactive molecule B

Question:

When BCl₃ gas is passed through an electric discharge, small amounts of the reactive molecule B₂Cl₄ are produced. (The molecule has a B—B covalent bond.)
(a) Draw a Lewis electron dot structure for B₂Cl₄.
(b) Describe the hybridization of the B atoms in the molecule and the geometry around each B atom.