Which of the following is not a
compound?
CO2, Chi, nací , ci

If you're talking about organic and inorganic compounds, they are all classified under one.

However, if you're talking about ionic and covalent compounds, they can be classified under them.

Carbon dioxide: Covalent

I believe you're talking about ChL, which could be considered a chemical compound or covalent.

NaCi does not exist. However, if you're talking about NaCl, which DOES exist, it is ionic.

Ci does not exist, but if it's Cl, once again, covalent.

Henceforth, I have no context. ChL OR NaCl could be considered the answer.

Why ChL? Chemical.

Why NaCl? It is the odd one out and ionic bonds are often considered a compound different from others.

The equation that describes the problem is  Fe(NO3)3(aq) + 3NaOH(aq) ---> Fe(OH)3(s) +  3 NaNO3(aq)
 
The Net ionic equation is written as follows:
 Fe^3(aq) + 3NO3-(aq) + 3Na+(aq) + 3OH-(aq) ---> Fe(OH)3(s) + 3Na+(aq) + 3NO^3-(aq)