The chelate effect is best attributed to considerations of which type?

Question

A. Enthalpy
B. Resonance
C. Entropy
D. Hydrogen Bonding
E. Hydration

Answer 1

The bonding in, say, an ethylenediamine (a.k.a. 1,2,diaminoethane) complex is of the same kind as in a complex of ammonia. So this rules out all the explanations except one.

Check: reactions of the type

[M(NH3)6]n+ + 3 en = M(en)3]n+ + 6 NH3

(en = ethylenediamine) have favorable equilibrium constants (this is what the chelate effect means).

There is only one consideration among those listed that accounts for this fact.

If you still haven't got it, think about the number of independent particles moving around at random in solution.