Preference of grignard between aldehyde and double bond? Quick question, in this reaction:

2-Butenal + CH3MgBr  -->  ??

Will the grignard attack the double-bond or the aldehyde carbon?
Please explain this preference, thanks!
The Grignard will first attack the aldehyde carbon, giving you a secondary alcohol. Since the alcohol is strongly polarized, it would be difficult for the double bond to be attacked.