Question

In each reaction box, place the best reagent or reactant from the list below. Reagents may be used more than once or not at all. Draw the intermediate products B and C (both are neutral; omit byproducts). The six reaction boxes of the labeling scheme are correct. Examine the drawing area(s) marked as incorrect.

Answer 1

Concepts and reason

• One or more substances reacting together to form a product is called a chemical reaction. Most chemical reactions take place with the help of reagents.

• Reagents are the substance used to transform one form of substance to another.

• The reaction undergoes a series of steps like deprotonation of an alkyne, substitution, and hydrogenation reactions to attain a final product.

Fundamentals

The reagents play a vital role in all the reactions. Each reagent plays a different role in the chemical reaction.

Deprotonation of alkynes: An alkyne undergoes deprotonation with the help of the reagent sodium amide $\left( {{\rm{NaN}}{{\rm{H}}_{\rm{2}}}} \right)$ . Acetylide ion forms when sodium amide reacts with an alkyne. Acetylide ion acts as a good nucleophile which undergoes a substitution reaction with alkyl halides and forms a new carbon chain.

Substitution: The nucleophilic substitution reaction $\left( {{{\rm{S}}_{\rm{N}}}{\rm{2}}} \right)$ takes place when the nucleophile undergoes reaction with alkyl halides.

Hydrogenation: The addition of ${{\rm{H}}_{\rm{2}}}$ in the presence of palladium is used to reduce alkenes and alkynes to alkanes.

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