Chapter 5, Problem 5.45P

Interpretation Introduction

(a)

Interpretation: The given groups are to be ranked in the order of decreasing priority.

Concept introduction: A carbon atom that has four nonequivalent atoms or groups attached to it is known as chiral carbon atom. Chiral carbon centers are also called as asymmetric or stereogenic centers.

The priorities of the atoms that are directly attached to the stereogenic center are assigned in the order of decreasing atomic number. An atom of highest atomic number gets highest priority.

Answer to Problem 5.45P

The decreasing order of priority is $-\text{OH}>-{\text{NH}}_{\text{2}}>-{\text{CH}}_{\text{3}}$.

Explanation of Solution

The priority can be assigned by numbering the groups which are bonded to the chiral carbon atom based on the molecular weight and electronegativity.

In the given groups, the atomic number of nitrogen is $7$, carbon is $6$ and oxygen is $8$. An atom of highest atomic number gets highest priority. Therefore, the decreasing order of priority is $-\text{OH}>-{\text{NH}}_{\text{2}}>-{\text{CH}}_{\text{3}}$.

Conclusion

The decreasing order of priority for the given groups is $-\text{OH}>-{\text{NH}}_{\text{2}}>-{\text{CH}}_{\text{3}}$.

Interpretation Introduction

(b)

Interpretation: The given groups are to be ranked in the order of decreasing priority.

Concept introduction: A carbon atom that has four nonequivalent atoms or groups attached to it is known as chiral carbon atom. Chiral carbon centers are also called as asymmetric or stereogenic centers.

The priorities of the atoms that are directly attached to the stereogenic center are assigned in the order of decreasing atomic number. An atom of highest atomic number gets highest priority.

Answer to Problem 5.45P

The decreasing order of priority for the given groups is $-{\left({\text{CH}}_{\text{2}}\right)}_{\text{3}}{\text{CH}}_{\text{3}}>{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}>{\text{CH}}_{\text{2}}{\text{CH}}_3>-{\text{CH}}_{\text{3}}$.

Explanation of Solution

The priority can be assigned by numbering the groups which are bonded to the chiral carbon atom based on the molecular weight and electronegativity.

The given groups are $-{\text{CH}}_{\text{3}}\text{, }-{\text{CH}}_{\text{2}}{\text{CH}}_3\text{, }-{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{, }-{\left({\text{CH}}_{\text{2}}\right)}_{\text{3}}{\text{CH}}_{\text{3}}$. When the stereogenic center contains same number of atoms attached to it then, the priority is assigned on the basis of the atomic number of atoms which are bonded to these atoms. An atom of highest atomic number gets highest priority.

Therefore, the decreasing order of priority for the given groups is $-{\left({\text{CH}}_{\text{2}}\right)}_{\text{3}}{\text{CH}}_{\text{3}}>{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}>{\text{CH}}_{\text{2}}{\text{CH}}_3>-{\text{CH}}_{\text{3}}$.

Conclusion

The decreasing order of priority for the given groups is $-{\left({\text{CH}}_{\text{2}}\right)}_{\text{3}}{\text{CH}}_{\text{3}}>{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}>{\text{CH}}_{\text{2}}{\text{CH}}_3>-{\text{CH}}_{\text{3}}$.

Interpretation Introduction

(c)

Interpretation: The given groups are to be ranked in the order of decreasing priority.

Concept introduction: A carbon atom that has four nonequivalent atoms or groups attached to it is known as chiral carbon atom. Chiral carbon centers are also called as asymmetric or stereogenic centers.

The priorities of the atoms that are directly attached to the stereogenic center are assigned in the order of decreasing atomic number. An atom of highest atomic number gets highest priority.

Answer to Problem 5.45P

The decreasing order of priority is $-{\text{NH}}_2>{\text{CH}}_{\text{2}}{\text{NHCH}}_{\text{3}}>-{\text{CH}}_{\text{2}}{\text{NH}}_2>-{\text{CH}}_{\text{3}}$.

Explanation of Solution

The priority can be assigned by numbering the groups which are bonded to the chiral carbon atom based on the molecular weight and electronegativity.

In the given groups, the atomic number of nitrogen is $7$ and carbon is $6$. An atom of highest atomic number gets highest priority. Therefore, $-{\text{NH}}_2$ gets highest priority. When the stereogenic center contains same number of atoms attached to it then, the priority is assigned on the basis of the atomic number of atoms which are bonded to these atoms. An atom of highest atomic number gets highest priority.

Hence, the decreasing order of priority is $-{\text{NH}}_2>{\text{CH}}_{\text{2}}{\text{NHCH}}_{\text{3}}>-{\text{CH}}_{\text{2}}{\text{NH}}_2>-{\text{CH}}_{\text{3}}$.

Conclusion

The decreasing order of priority for the given groups is $-{\text{NH}}_2>{\text{CH}}_{\text{2}}{\text{NHCH}}_{\text{3}}>-{\text{CH}}_{\text{2}}{\text{NH}}_2>-{\text{CH}}_{\text{3}}$.

Interpretation Introduction

(d)

Interpretation: The given groups are to be ranked in the order of decreasing priority.

Concept introduction: A carbon atom that has four nonequivalent atoms or groups attached to it is known as chiral carbon atom. Chiral carbon centers are also called as asymmetric or stereogenic centers.

The priorities of the atoms that are directly attached to the stereogenic center are assigned in the order of decreasing atomic number. An atom of highest atomic number gets highest priority.

Answer to Problem 5.45P

The decreasing order of priority is $-\text{COOH > }-\text{CHO > }-{\text{CH}}_{\text{2}}\text{OH > }-\text{H}$.

Explanation of Solution

The priority can be assigned by numbering the groups which are bonded to the chiral carbon atom based on the molecular weight and electronegativity.

In the given groups, the atomic number of carbon is $6$, oxygen is $8$ and hydrogen is $1$. An atom of highest atomic number gets highest priority. Therefore, $-\text{H}$ gets lowest priority. For an atom which is a part of multiple bonds, the priority is assigned by treating the number of multiple bonded atoms equivalent to the number of singly bonded atoms. Among $-\text{COOH, }-{\text{CH}}_{\text{2}}\text{OH, }-\text{CHO}$, the priority is assigned as,

Figure 1

Hence, the decreasing order of priority is $-\text{COOH > }-\text{CHO > }-{\text{CH}}_{\text{2}}\text{OH > }-\text{H}$.

Conclusion

The decreasing order of priority for the given groups is $-\text{COOH > }-\text{CHO > }-{\text{CH}}_{\text{2}}\text{OH > }-\text{H}$.

Interpretation Introduction

(e)

Interpretation: The given groups are to be ranked in the order of decreasing priority.

Concept introduction: A carbon atom that has four nonequivalent atoms or groups attached to it is known as chiral carbon atom. Chiral carbon centers are also called as asymmetric or stereogenic centers.

The priorities of the atoms that are directly attached to the stereogenic center are assigned in the order of decreasing atomic number. An atom of highest atomic number gets highest priority.

Answer to Problem 5.45P

The decreasing order of priority is $-\text{Cl}>-\text{SH}>-\text{OH}>-{\text{CH}}_{\text{3}}$.

Explanation of Solution

The priority can be assigned by numbering the groups which are bonded to the chiral carbon atom based on the molecular weight and electronegativity.

In the given groups, the atomic number of chlorine is $17$, sulphur is $16$, carbon is $6$ and oxygen is $8$. An atom of highest atomic number gets highest priority. Therefore, the decreasing order of priority is $-\text{Cl}>-\text{SH}>-\text{OH}>-{\text{CH}}_{\text{3}}$.

Conclusion

The decreasing order of priority for the given groups is $-\text{Cl}>-\text{SH}>-\text{OH}>-{\text{CH}}_{\text{3}}$.

Interpretation Introduction

(f)

Interpretation: The given groups are to be ranked in the order of decreasing priority.

Concept introduction: A carbon atom that has four nonequivalent atoms or groups attached to it is known as chiral carbon atom. Chiral carbon centers are also called as asymmetric or stereogenic centers.

The priorities of the atoms that are directly attached to the stereogenic center are assigned in the order of decreasing atomic number. An atom of highest atomic number gets highest priority.

Answer to Problem 5.45P

The decreasing order of priority for the given groups is $-\text{C}\equiv \text{CH > }-\text{CH}={\text{CH}}_2\text{ > }-\text{CH}{\left({\text{CH}}_3\right)}_2\text{ > }-{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}$.

Explanation of Solution

The priority can be assigned by numbering the groups which are bonded to the chiral carbon atom based on the molecular weight and electronegativity.

An atom of highest atomic number gets highest priority. Therefore, in the given groups, $-{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}$ gets lowest priority.

For an atom which is a part of multiple bonds, the priority is assigned by treating the number of multiple bonded atoms equivalent to the number of singly bonded atoms. Among, $-\text{C}\equiv \text{CH, }-\text{CH}{\left({\text{CH}}_3\right)}_2\text{, }-\text{CH}={\text{CH}}_2$ the priority is assigned as,

Figure 2

Hence, the decreasing order of priority for the given groups is $-\text{C}\equiv \text{CH > }-\text{CH}={\text{CH}}_2\text{ > }-\text{CH}{\left({\text{CH}}_3\right)}_2\text{ > }-{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}$.

Conclusion

The decreasing order of priority for the given groups is $-\text{C}\equiv \text{CH > }-\text{CH}={\text{CH}}_2\text{ > }-\text{CH}{\left({\text{CH}}_3\right)}_2\text{ > }-{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}$.