grignard reagents

a.  Give the reaction scheme, showing the products formed (before hydrolysis) when one equivalent of ethylmagnesium bromide is treated with one equivalent of 5-hydroxy-2pentanone.  Does addition of two equivalents of Grignard reagent to this yield a different product(s)? If so, give the structure(s).
b.  Explain why Grignard reagents cannot be prepared from an organic halide that also contains a hydoxyl, a carboxyl, a thiol, or amino group.
c.  What would be the final product of the reaction between methyl benzoate and two equivalents of ethylmagnesium bromide?  
d.  Consider the same reaction as in the case of question C except that it is carried out with ethyl benzoate.  What product would be expected in this case?  
e.  Grinard reagents may be used to prepare other organometallic reagents, for example, ethylmagnesium bromide with cadmium chloride to yield diethylcadmium.
    2CH3CH2MgCl + CdCl2 ---->(CH3CH2)2Cd+2MgCl2
Indicate the product of the following reactions and name the organometallic product.
  1.4CH3MgCl+SiCl4----> ?
  2.  C6H5MgCl+HgCl2----> ?