[NewtoAtoms]

For which reaction is the equilibrium constant the greatest?

a. 1
b. 2
c. 3
d. 4

I have done the leg work I just would appreciate some guidance.
I know that equilibrium constant are greater of aldehydes than for ketones
However these are all aldehydes therefore I am forced to examine the substituents.

                       OH
                       l
1. CH3CH2CH2 - C - H                                       C (OH, H, CN, CH2CH2CH3)
                       l
                       CN

                       OH
                       l
2.  CH3CH2CF2- C - H                                        C (OH, H, CN, CH3CH2CF2)
                       l
                       CN

               OH
               l
3. CH3CH2CCH3                                                 C (OH, CH3, CN, CH2CH3)
               l
               CN

                OH
                l
4.  CH3CF2CCH3                                                 C (OH, CH3, CN, CH3,CF2)
                l
                CN

Looking at the above substituents that are attached to the C, I would conclude that 1 has the greatest equilibrium constant because according to the steric affects, it is less crowded in comparison with the others.

Can anyone tell me if my reasoning is correct?

Thank you for your help and time.
Have a great day.

New to Atoms.

[nj_bartel]

Those aren't all aldehydes (3 is actually the least reactive of any of them).

[NewtoAtoms]

Pardon me, I apologize for my mistake.
Yes 1 and 2 are aldehydes and 3 and 4 are ketones. 
According to my notes, aldehydes have a greater equilibrium constant than ketones, therefore either 1 or 2 would be have the greatest equilibrium constant. Because they are both aldehydes, I should then compare the substituents correct? In comparison #2 has 2 F's attached therefore the crowding is more and the equilibrium constant is lower than that of 1.  Is this correct?  Is my reasoning correct or am I totally missing something.

Thank you for your time

New to atoms

[sjb]

Actually, the size difference between a fluorine and a hydrogen in these circumstances isn't that much. I'd perhaps look into electronics as well as sterics.

S

[McCoy]

I can choose #2 because there are 2 electron rich species on the alpha carbon.