Question

Synergic back-bonding is absent in transition metal carbonyls.
If true enter 1, else enter 0.

Answer 1

The answer is 0.

Synergic back bonding is present in transition metal carbonyls.

$\pi$ backbonding is a concept in which electrons move from an atomic orbital on one atom to a ${\pi }^{\ast }$ antibonding orbital on a $\pi$ acceptor ligand. It is especially common in the organometallic chemistry of transition metals with multi-atomic ligands such as carbon monoxide, ethylene or the nitrosonium cation.

An example is shown above.