Question 1

Select the potential energy diagram that represents an exothermic (exergonic)reaction.

Accepted Answer

A

Question 2

Consider the reaction of 2-chloro-2-methylpentane with sodium iodide.  Assuming no other changes,how would it affect the rate if one simultaneously doubled the concentration of 2-chloro-2-methylpentane and sodium iodide?

Accepted Answer

The rate of a chemical reaction is dependent on the concentration of the reactants. Doubling the concentration of both 2-chloro-2-methylpentane and sodium iodide would lead to an increase in the number of collisions between the two reactants, resulting in an increase in the rate of the reaction. The rate would double because the concentration of both reactants has doubled. Therefore, the correct answer is (B) It would double the rate.

Question 3

The reaction, has the following thermodynamic values at 27ºC: $\Delta$H = -75.3 kJ mol^-1; $\Delta$S = 54.4 J K^-1 mol^-1.What is the value of $\Delta$G for this reaction?

Accepted Answer

E

Question 4

Increasing the temperature of a chemical reaction usually increases greatly the rate of the reaction.The primary reason for this is that increasing the temperature:

Accepted Answer

The answer of Increasing the temperature of a chemical reaction...

Question 5

The rate equation for a nucleophilic substitution reaction of a secondary alkyl chloride (R-Cl)with I^-ion would be:

Accepted Answer

The rate equation for a nucleophilic substitution reaction (SN2) involving a secondary alkyl chloride and a nucleophile is dependent on the concentrations of both the alkyl halide and the nucleophile. This is because the reaction proceeds in a single, concerted step where both the substrate (R-Cl) and the nucleophile (in this case represented by a placeholder symbol) come together to form the transition state, leading to the product. Therefore, the rate of reaction is proportional to the concentration of both reactants.

Question 6

An increase in the temperature at which a reaction is carried out increases:

Accepted Answer

An increase in temperature increases both the collision frequency (due to increased molecular speed) and the fraction of molecules with energy greater than the activation energy (due to increased kinetic energy). Both of these factors contribute to an increase in the reaction rate. The fraction of molecules with proper orientation is not affected by temperature, as proper orientation is determined by the geometry of the reactants and is not affected by kinetic energy.

Question 7

Increasing the temperature of a chemical reaction usually increases greatly the rate of the reaction.The most important reason for this is that increasing the temperature:

Accepted Answer

Increasing the temperature increases the kinetic energy of the particles, which enhances their ability to overcome the activation energy barriers. As a result, a larger fraction of molecules will have energy greater than the activation energy threshold and will be able to react when they collide. Therefore, the higher temperature increases the fraction of collisions with energy greater than the activation energy (E_act), which significantly boosts the reaction rate.

Question 8

Consider the S_N2 reaction of butyl bromide with OH^- ion. CH₃CH₂CH₂CH₂Br + OH^-$\rightarrow$CH₃CH₂CH₂CH₂OH + Br^- Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both butyl bromide and OH^- ion?

Accepted Answer

In an S_N2 reaction, the rate is dependent on the concentration of both the substrate (butyl bromide) and the nucleophile (OH^-). Doubling both concentrations results in a fourfold increase in the rate (2 x 2 = 4).

Question 9

Which will be true for any actual or potential nucleophilic substitution reaction?

Accepted Answer

The activation energy for a nucleophilic substitution reaction ($\Delta G^{\ddagger}$) is always positive, indicating that energy must be supplied to reach the transition state from the reactants.

Question 10

For the typical S_N2 reaction Y^- + RX $\rightarrow$RY + X^- It can be predicted that $\Delta$S^‡ will be:

Accepted Answer

In an S_N2 reaction, the transition state is more ordered than the reactants due to the formation of a bond between the nucleophile and the substrate while the leaving group is still partially attached. This increased order results in a negative entropy change (ΔS^‡).

Question 11

What product(s)would you expect to obtain from the following S_N2 reaction?

Accepted Answer

The answer of What product(s)would you expect to obtain from...

Question 12

Consider the S_N2 reaction of 2-iodopentane with CH₃CO₂- ion. Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both 2-iodopentane and CH₃CO₂- ion?

Accepted Answer

The answer of Consider the S_N2 reaction of 2-iodopentane with...

Question 13

The rate equation for a nucleophilic substitution reaction of a tertiary alkyl bromide (R-Br)with I ^- ion would be:

Accepted Answer

The rate equation for nucleophilic substitution reaction of a tertiary alkyl bromide with a negatively charged ion does not depend on the concentration of the negatively charged ion. Rather, it only depends on the concentration of the alkyl bromide. Thus, the correct rate equation is Rate = k [RBr].

Question 14

Select the potential energy diagram that represents a two-step endothermic (endergonic)reaction.

Accepted Answer

Only diagram II shows a two-step endothermic (endergonic) reaction, where the reactants have lower energy than the products. The first step is endothermic and requires energy, while the second one is exothermic and releases energy. The other diagrams either show an exothermic reaction or a single-step endothermic reaction.

Question 15

A true statement about the transition state(s)of an S_N2 reaction is:

Accepted Answer

The single transition state represents the point of maximum free energy of the reaction. This is because the transition state refers to the point in the reaction pathway where the reactants are in the process of transforming into the products, and as such requires the most energy to overcome the activation energy barrier.

Question 16

The hybridization state of the charged carbon in a carbocation is

Accepted Answer

The answer of The hybridization state of the charged carbon...

Question 17

The major product of the following reaction would be:

Accepted Answer

The answer of The major product of the following reaction...

Question 18

Select the rate law for the following reaction,e.g. , CH₃CH₂CH₂CHBrCH₃ + OH ^- $\rightarrow$CH₃CH₂CH₂CHOHCH₃ + X ^- ( RBr )

Accepted Answer

The rate law for the given reaction is simply the concentration of RBr multiplied by the concentration of OH-. This is because the given reaction is a bimolecular reaction and involves the collision of RBr and OH- molecules. Thus, the correct choice is option B.

Question 19

Consider the S_N2 reaction of 1-chloro-5-methylhexane with CN-ion. Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both 1-chloro-5-methylhexane and CN- ion?

Accepted Answer

Based on the rate law, rate = k[1-chloro-5-methylhexane][CNF1F1F1S1F1F1F10 ion]
When both concentrations are doubled, the rate will increase by a factor of 2 x 2 = 4. Therefore, the correct answer is D.

Question 20

The difference in the bond energies of reactants and the transition state of a reaction is designated by the notation:

Accepted Answer

The notation "F1F1F1S1" represents the starting state or reactants, "F1F1F10" represents the product state, "H^{" represents the transition state, and "‡}" represents the activation energy barrier or difference in bond energies between the reactants and transition state. Therefore, choice B is the correct answer.

Quiz 6: Ionic Reactions - Nucleophilic Substitution and Elimination Reactions of Alkyl Halides

Select the potential energy diagram that represents an exothermic (exergonic) reaction.

Consider the reaction of 2-chloro-2-methylpentane with sodium iodide. Assuming no other changes,how would it affect the rate if one simultaneously doubled the concentration of 2-chloro-2-methylpentane and sodium iodide?

Increasing the temperature of a chemical reaction usually increases greatly the rate of the reaction.The primary reason for this is that increasing the temperature:

The rate equation for a nucleophilic substitution reaction of a secondary alkyl chloride (R-Cl) with I^-ion would be:

An increase in the temperature at which a reaction is carried out increases:

Increasing the temperature of a chemical reaction usually increases greatly the rate of the reaction.The most important reason for this is that increasing the temperature:

Consider the S_N2 reaction of butyl bromide with OH^- ion. CH₃CH₂CH₂CH₂Br + OH^- $\rightarrow$ CH₃CH₂CH₂CH₂OH + Br^- Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both butyl bromide and OH^- ion?

Which will be true for any actual or potential nucleophilic substitution reaction?

For the typical S_N2 reaction Y^- + RX $\rightarrow$ RY + X^- It can be predicted that $\Delta$ S^‡ will be:

What product(s) would you expect to obtain from the following S_N2 reaction?

Consider the S_N2 reaction of 2-iodopentane with CH₃CO₂- ion. Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both 2-iodopentane and CH₃CO₂- ion?

The rate equation for a nucleophilic substitution reaction of a tertiary alkyl bromide (R-Br) with I ^- ion would be:

Select the potential energy diagram that represents a two-step endothermic (endergonic) reaction.

A true statement about the transition state(s) of an S_N2 reaction is:

The hybridization state of the charged carbon in a carbocation is

The major product of the following reaction would be:

Select the rate law for the following reaction,e.g. , CH₃CH₂CH₂CHBrCH₃ + OH ^- $\rightarrow$ CH₃CH₂CH₂CHOHCH₃ + X ^- ( RBr )

Consider the S_N2 reaction of 1-chloro-5-methylhexane with CN-ion. Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both 1-chloro-5-methylhexane and CN- ion?

The difference in the bond energies of reactants and the transition state of a reaction is designated by the notation:

Quiz 6: Ionic Reactions - Nucleophilic Substitution and Elimination Reactions of Alkyl Halides

Select the potential energy diagram that represents an exothermic (exergonic) reaction.

Consider the reaction of 2-chloro-2-methylpentane with sodium iodide. Assuming no other changes,how would it affect the rate if one simultaneously doubled the concentration of 2-chloro-2-methylpentane and sodium iodide?

The reaction, has the following thermodynamic values at 27ºC: Δ\DeltaΔ H = -75.3 kJ mol-1; Δ\DeltaΔ S = 54.4 J K-1 mol-1.What is the value of Δ\DeltaΔ G for this reaction?

Increasing the temperature of a chemical reaction usually increases greatly the rate of the reaction.The primary reason for this is that increasing the temperature:

The rate equation for a nucleophilic substitution reaction of a secondary alkyl chloride (R-Cl) with I-ion would be:

An increase in the temperature at which a reaction is carried out increases:

Increasing the temperature of a chemical reaction usually increases greatly the rate of the reaction.The most important reason for this is that increasing the temperature:

Consider the SN2 reaction of butyl bromide with OH- ion. CH3CH2CH2CH2Br + OH- →\rightarrow→ CH3CH2CH2CH2OH + Br- Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both butyl bromide and OH- ion?

Which will be true for any actual or potential nucleophilic substitution reaction?

For the typical SN2 reaction Y- + RX →\rightarrow→ RY + X- It can be predicted that Δ\DeltaΔ S‡ will be:

What product(s) would you expect to obtain from the following SN2 reaction?

Consider the SN2 reaction of 2-iodopentane with CH3CO2- ion. Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both 2-iodopentane and CH3CO2- ion?

The rate equation for a nucleophilic substitution reaction of a tertiary alkyl bromide (R-Br) with I - ion would be:

Select the potential energy diagram that represents a two-step endothermic (endergonic) reaction.

A true statement about the transition state(s) of an SN2 reaction is:

The hybridization state of the charged carbon in a carbocation is

The major product of the following reaction would be:

Select the rate law for the following reaction,e.g. , CH3CH2CH2CHBrCH3 + OH - →\rightarrow→ CH3CH2CH2CHOHCH3 + X - ( RBr )

Consider the SN2 reaction of 1-chloro-5-methylhexane with CN-ion. Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both 1-chloro-5-methylhexane and CN- ion?

The difference in the bond energies of reactants and the transition state of a reaction is designated by the notation:

The rate equation for a nucleophilic substitution reaction of a secondary alkyl chloride (R-Cl) with I^-ion would be:

Consider the S_N2 reaction of butyl bromide with OH^- ion. CH₃CH₂CH₂CH₂Br + OH^- $\rightarrow$ CH₃CH₂CH₂CH₂OH + Br^- Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both butyl bromide and OH^- ion?

For the typical S_N2 reaction Y^- + RX $\rightarrow$ RY + X^- It can be predicted that $\Delta$ S^‡ will be:

What product(s) would you expect to obtain from the following S_N2 reaction?

Consider the S_N2 reaction of 2-iodopentane with CH₃CO₂- ion. Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both 2-iodopentane and CH₃CO₂- ion?

The rate equation for a nucleophilic substitution reaction of a tertiary alkyl bromide (R-Br) with I ^- ion would be:

A true statement about the transition state(s) of an S_N2 reaction is:

Select the rate law for the following reaction,e.g. , CH₃CH₂CH₂CHBrCH₃ + OH ^- $\rightarrow$ CH₃CH₂CH₂CHOHCH₃ + X ^- ( RBr )

Consider the S_N2 reaction of 1-chloro-5-methylhexane with CN-ion. Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both 1-chloro-5-methylhexane and CN- ion?