Which one will get a higher chance of critical?

Question

serene grace +air slash or super luck+airslash

Answer 1

Serene Grace with Air Slash because its a chance to Flinch not a critical hit chance.

Answer 2

Serene Grace would increase the flinch chance of Air Slash to 60%. Serene Grace has nothing to do with critical hit.

Super Luck would raise the critical hit ratio of any move by 1 stage. Super Luck is the ability you want for a higher crit. rate.