Which of the following reactions is a dehydration reaction?

Question

A.  A + H2O ® B + C  
B.  A + B + H2O ® C
C.  A ® B + C+ H2O
D.  A + B ® C + H2O

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?
· What key words does the question contain and what do they mean?

Gather Content
· What do you know about dehydration reactions? How does it relate to the question?

Consider Possibilities  
· What other information is related to the question? Which information is most useful?

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

D.  A + B ® C + H2O

Clarify Question
· What is the key concept addressed by the question?
        o The question asks about dehydration reactions.
· What type of thinking is required?
        o You are being asked to apply your knowledge of dehydration reactions to identify one.
· What key words does the question contain and what do they mean?
        o Dehydration reaction – these are reactions used to link two monomers together, releasing water.

Gather Content
· What do you know about dehydration reactions? How does it relate to the question?
        o Dehydration reactions are used to join two monomers together.
        o Water is released in the reaction.

Consider Possibilities  
· What other information is related to the question? Which information is most useful?
        o The two reactions with water on the reactant side of the reaction (left side) are using water and are thus not dehydration reactions.  A + B + H2O ® C and A + H2O ® B + C  
        o Reactions with one reactant and two products are breaking down a compound and not synthesizing molecules.  A + H2O ® B + C  and   A ® B + C+ H2O

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o The best answer is A + B ® C + H2O.  In this case the two reactants A and B are being joined together to form the product C.  Water is generated in the reaction making it a dehydration.

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o This question asked you to apply the definition of a dehydration reaction to identify it from several examples. If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did you recall the definition of a dehydration reaction and that water was a product?  Did you realize that in addition to producing water these involve synthesizing a polymer from two monomers?