As opposed to the carbon-carbon double bond introduction to the molecule a carbo
ID: 929481 • Letter: A
Question
As opposed to the carbon-carbon double bond introduction to the molecule a carbon-oxygen double bond does not result in the formation of cis- or trans-isomers. Why? A. C-O group is stronger than C-C bond B. C-O group is more polar than C-C bond C. Oxygen is connected to only one atom D. Rotation around the C-O is too difficult E. Oxygen is more electronegative than carbon 15. "Reactivity in the S,2 reaction decreases in the following order 1-Chloropropane >2-Chloropropane 2-Chloro-2-methylpropane." What is your opinion about this statement? A. True, because the steric hindrance increases in this order B. False, because stability of the carbocation increases in this order C/True, because the leaving group is involved in the rate-limiting step D. True, because stability of the final product increases in this order E. False, because nucleophilicity increases in this order 16. Choose the correet relationship between the following pair of structures: A. Enantiomers B. Constitutional (structural) isomers C. Identical E. Not isomers 17. It is known, that water slowly converts tert.butyl bromide into 2-methyl-2-propanol, which involves the Syl reaction. What other reaction step (besides the Ssl sequence) is involved in this mechanism? A. Protonation B. Deprotonation C.Elimination E. Free radical propagation step D. S2 reaction 18. Sodium iodide failed to convert bromoethane to 1-iodopropane by nucleophilic substitution. Apply the material you have learned in this course and identify the reason why the reaction was unsuccessful. A. The nucleophile is too weak B. Carbocation would be too unstable C. The leaving group is too badD. The organic halide is wrong E. The nucleophile is wrongExplanation / Answer
Cis-trans nomenclature: if identical groups are attached to the double bond then we give cis-trans nomenclature.
Cis isomer: Two identical groups are present on the same side of the double bond.
Trans isomer: Two identical groups are present on opposite side of the double bond.
In carbonyl compound of oxygen is connected to only one atom. Hence, it is not show cis-trans isomerism. Therefore, the correct option is “C”.
15.
SN2 attack on a simple primary alkyl halide is unhindered. Attack on sterically hindered is impossible.
Therefore, the correct option is A.
16.
R and S configuration can be assign to the compound by using the following CIP (Cahn-Ingold-Prelog) sequence rules:
Chirality center: An atom (usually carbon) which is bonded to four different atoms or groups is known as chiral center.
Rule 1: Select the chiral center in the compound and assign priorities to the atoms based on its atomic number. The atom which is having highest atomic number gets the first priority and atom which is having least atomic number (usually hydrogen) fourth priority.
Rule 2: If the isotopes of same atom are attached to the chiral center, then then atom with the higher atomic mass receives higher priority.
Rule 3: If the first atom of each substituent is same then give priority to the second atom in the each substituent. This process in continue to the third and fourth until the rule difference is reached.
Rule 4: If the substituents have multiple bonds, the multiple bonded atoms are considered as same number of single boned atoms.
Example:
If the priority order of the substituents from highest to second highest to third highest is in clock wise direction then the chiral center has R configuration ( Latin rectus means right).
If the priorities order of the substituents from highest to second highest to third highest is counter clock wise direction then the chiral center has S configuration (Latin sinister means left).
If the least priority substituent (usually hydrogen) is present on the above the plane then its configuration is reversed.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.