What is the chemical formula of Tartar Emetic?

What is the name of the complex formed by the coordination reaction of carbon monoxide?

Select the correct statement about the anionic part of Zeise's salt,$K[Pt(\eta^2 - C_2H_4)Cl_3]$.

Back bonding is involved in which of the following organometallic compounds?

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: The metal-carbon bond in metal carbonyls possesses both $\sigma$ and $\pi$ character.
Reason $(R)$: The ligand-to-metal bond is a $\sigma$ bond and metal-to-ligand bond is a $\pi$ bond.
In the light of the above statements,choose the most appropriate answer from the options given below :

The correct sequence of $CO$ bond order in the given compounds is:
$(P) \ Fe(CO)_5, (Q) \ CO, (R) \ H_3B \leftarrow CO, (S) \ [Mn(CO)_5]^-$