1. Which one is bulkier of the two between PPh₃ and PCy₃?

PCy₃

2. What is the maximum number of phosphine ligand that can bind to a single metal center?

Six, for example in W(PMe₃)₆

3. Halides and alkoxides are what type of ligands?

σ−donor and π−donor

σ−donor and π−donor