Chelation

Q. $M{g}_2{C}_3$ reacts with water forming propyne. $C_3^{4-}$ has:

1. Two sigma and two pi bonds
2. Three sigma and one pi bonds
3. Two sigma and one pi bonds
4. Two sigma and three pi bonds

Q. Which one of the following form a chelate ring

1. acetate
2. oxalate
3. cyanide
4. ammonia

Q. Which of the following ligands form a chelate

1. Acetate
2. Oxalate
3. Cyanide
4. Ammonia

Q. Low spin tetrahedral complexes are not formed because :

1. electrons do not go to $e$ in case of tetrahedral complexes
2. for tetrahedral complexes, the CFSE is higher than pairing energy.
3. tetrahedral compleces are formed by weak field ligands only.
4. for tetrahedral complexes, the CFSE is lower than pairing energy.