a. 11. Draw a precursor of .... an aldehyde (RHC=0) b .: a ketone (RzC0) noon a carboxylic acid (RCO H) C. 14. Lithium and Grignard reagents are extremely strong bases. Upon making a bond to H* they pka units of energy to remove an H.) release a large amount of energy (you may assume about 50 pKa units , but actually the value is closer to 35-40 pKa units of energy). Recall that the pKa of an alcohol is about 16. (Requires 16 a. In the reaction below, the moment a molecule of Grignard reagent is formed, it immediately undergoes an acid-base reaction with a second molecule of starting material. Use curved arrows to show this unwanted side reaction, and draw the products. H2 H2 H Br + MgBr Mg metal bond to releases -35 pKa units CH . starting alkyl halide H2 side-reaction H Br H2 requires +16 pKa units to break starting alkyl halide is in excess in the reaction mixture b. Construct an explanation for why preparation of lithium and Grignard reagents cannot be performed with an alkyl halide containing an H with a pK,