Choose the statements that accurately describe the Wittig reaction.

STRATEGY: Review the characteristics of the Wittig reaction. Consider the types of reactants involved, the type of transformation that occurs, and the types of products that result.

A. the product is an ylide
B. involves a ylide as a reactant/intermediate
C. results in a betaine intermediate
D. a ketone is a required reactant
E. a C=C bond becomes saturated

B. Involves a ylide as a reactant/intermediate  

C. Results in a betaine intermediate

Explanation:

The Wittig reaction is the reaction of an aldehyde or ketone with a triphenylphosphonium ylide to form an alkene.

A betaine intermediate is the precursor to an oxaphosphetane intermediate.

A. is wrong. The ylide is a reactant/intermediate.

D. is wrong. The reactant can be an aldehyde

E. is wrong. A C=O bond becomes a C=C bond.

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6