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Example Questions
Example Question #1 : Reactions Types
In an addition reaction
one sigma bond is broken, and one sigma bond is formed
none of these
one pi bond is broken, and two sigma bonds are formed
one pi bond is broken, and one pi bond is formed
two sigma bonds are broken, and one pi bond is formed
one pi bond is broken, and two sigma bonds are formed
Addition reactions involve breaking one pi bond (double bond) and forming two sigma bonds in the product.
Example Question #96 : Organic Chemistry
A compound can be hydrogenated by platinum metal and hydrogen to give
. How many rings and double bonds does the original compound have?
The original compound has no triple bonds.
3 double bonds and 1 ring
3 double bonds and 2 rings
None of the other answers
4 double bonds and 1 ring
4 double bonds and 2 rings
3 double bonds and 2 rings
Hydrogenation of a double bond involves the bond breaking and a hydrogen being added to each carbon of that double bond. You can tell the number of double bonds by taking the number of hydrogens added and dividing it by 2.
6 added hydrogen divided by 2 is 3 double bonds.
A hydrocarbon with zero degrees of unsaturation and carbons has
hydrogens. For every two hydrogens less than
, there is one degree of unsaturation. After hydrogenation, our final product has no double bonds. After calculation, we see that it has two degrees of unsaturation. This means that it has two rings.
Example Question #1 : Help With Addition Reactions
Which of the following reagents are required to convert 1-pentene to pentane?
Methanol
In order to convert an alkene into an alkane, we need a catalyst.
Example Question #1 : Help With Addition Reactions
Ph = phenyl = benzene
Which reagent would work best to convert into
?
We can reduce the alkene here by simply adding two hydrogens with as a reagent.
Example Question #1 : Reactions Types
Suppose that the given reactant, 1-hexene, is reacted with in the presence of ultraviolet light. Which of the following is the major product?
In this question, we're told that our starting material, 1-hexene, is being reacted with hydrobromic acid in the presence of ultraviolet (UV) light. To solve this, we need to consider how halogens add to alkenes, specifically in the presence of ultraviolet light.
First, it's important to note that UV light will cause the hydrogen and bromine atoms in to dissociate as free radicals. Because each of these atoms are electron deficient, they desperately want to react in order to fill their valence shells. And since the double bond in the alkene is electron dense, a reaction will occur between one of the electrons in this double bond and the free radical bromine.
The bromine radical adds to the alkene first at the 1-carbon in an anti-Markovnikov fashion. The reason it adds to this carbon (and not the 2-carbon) is because a secondary free radical is more stable than a primary free radical. Upon formation of this secondary radical, it will react with the hydrogen free radical in solution to generate the finished product, 1-bromohexane.
Example Question #1 : Help With Addition Reactions
Which of the following electrophiles is matched incorrectly with its catalyst needed for electrophilic aromatic substitution on a benzene ring?
All are correctly matched
A catalyst is often required for an electrophilic aromatic substitution reaction. All reagents are paired with their correct catalysts except for .
requires
as a catalyst in order to react with benzene.
Example Question #4 : Reactions Types
Classify the type of reaction given.
Rearrangement
Substitution
Addition
Elimination
Addition
An addition reaction is a reaction in which the reactants react to combine and form one product. It is the opposite of an elimination reaction. In the reaction given, the reactants hydrochloric acid and ethylene combine to form the product 1-chloropropane.
Example Question #1 : Reactions Types
Classify the type of reaction given.
Substitution
Elimination
Rearrangement
Addition
Addition
An addition reaction is a reaction in which the reactants react to combine and form one product. It is the opposite of an elimination reaction. In the reaction given, the reactants 2-butene and molecular hydrogen combine to form the product butane.
Example Question #1 : Reactions Types
Classify the type of reaction given.
Rearrangement
Elimination
Addition
Substitution
Addition
An addition reaction is a reaction in which the reactants react to combine and form one product. It is the opposite of an elimination reaction. In the reaction given, the reactants hydrochloric acid and propyne combine to form the product 2-chloropropene.
Example Question #1 : Reactions Types
Classify the type of reaction given above.
Elimination
Addition
Rearrangement
Substitution
Addition
An addition reaction is a reaction in which the reactants react to combine and form one product. It is the opposite of an elimination reaction. In the reaction given, the reactants hydrobromic acid and propene combine to form the product 2-bromopropane.
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