Chapter 22, Problem 1DE

(a)

Interpretation Introduction

To determine: An experiment that identifies the given substances.

Answer to Problem 1DE

Solution:

• ${\text{NF}}_{\text{3}}$ exist as gas.
• ${\text{PF}}_{\text{3}}$ exist as gas.
• ${\text{PF}}_5$ exist as gas.
• ${\text{PCl}}_{\text{3}}$ exist as liquid.
• ${\text{PCl}}_5$ exist as solid.

Explanation of Solution

The physical state of the substance depends upon the size of the substance.

The size of the atoms decreases from left to left along the period and increases down the group.

Nitrogen and fluorine belongs to second period. Phosphorous and chlorine belongs to third period. Therefore, the compounds to nitrogen and fluorine and phosphorous and fluorine are smaller in size and hence are in gaseous state. The compounds of phosphorous and chlorine are relatively larger in size. Phosphorous pentachloride is heavier since it contains a greater number of atoms and therefore, it exists as solid and phosphorous trichloride exist as liquid.

Thus,

• ${\text{NF}}_{\text{3}}$ exist as gas.
• ${\text{PF}}_{\text{3}}$ exist as gas.
• ${\text{PF}}_5$ exist as gas.
• ${\text{PCl}}_{\text{3}}$ exist as liquid.
• ${\text{PCl}}_5$ exist as solid.

Conclusion

• ${\text{NF}}_{\text{3}}$ exist as gas.
• ${\text{PF}}_{\text{3}}$ exist as gas.
• ${\text{PF}}_5$ exist as gas.
• ${\text{PCl}}_{\text{3}}$ exist as liquid.
• ${\text{PCl}}_5$ exist as solid.

(b)

Interpretation Introduction

To determine: The approach to determine the physical state of the given compounds using internet.

Answer to Problem 1DE

Solution: The physical state of the substance is estimated by knowing the melting and boiling point of the substance.

Explanation of Solution

The physical state is the state of the substance at room temperature. Therefore, by determining the melting point and boiling point of the substance, the physical state is estimated.

If the substance boils at the temperature less than the room temperature, than the physical state of the substance is gas.

If the substance boils at the temperature more than the room temperature, than the physical state of the substance is liquid.

If the substance melts at the temperature more than the room temperature, than the physical state of the substance is solid.

Conclusion

The physical state of the substance is estimated by knowing the melting and boiling point of the substance.

(c)

Interpretation Introduction

To determine: The substance that undergoes the reaction to add more atoms around the central atom.

Answer to Problem 1DE

Solution: The substance that undergoes the reaction to add more atoms around the central atom are ${\text{PF}}_{\text{3}}$ and ${\text{PCl}}_{\text{3}}$ .

Explanation of Solution

The atom that exhibit $d-\text{orbital}$ should have the principle quantum number of three or more.

Phosphorous possess the principle quantum number of three and nitrogen possess the principle quantum number of two.

Therefore, only phosphorous show the presence of vacant $d-\text{orbital}$ .

Nitrogen shares only three valence electrons out of five due to absence of vacant $d-\text{orbital}$ but phosphorous has the ability to share all the five valence electrons by undergoing hybridization of the five orbitals including vacant $d-\text{orbital}$ .

Thus, ${\text{PF}}_{\text{3}}$ reacts with fluorine molecule to form ${\text{PF}}_5$ and ${\text{PCl}}_{\text{3}}$ reacts with chlorine molecule to form ${\text{PCl}}_5$ .

Conclusion

The substance that undergoes the reaction to add more atoms around the central atom are ${\text{PF}}_{\text{3}}$ and ${\text{PCl}}_{\text{3}}$ due to the presence of vacant $d-\text{orbital}$ .

(d)

Interpretation Introduction

To determine: The substances that is likely to be solid.

Answer to Problem 1DE

Solution: The substances that is likely to be solid are ${\text{PF}}_5$ and ${\text{PCl}}_5$ .

Explanation of Solution

The physical state depends upon the intermolecular force of attraction between the molecules.

The more the polarity of the substance, the stronger is the intermolecular force of attraction.

${\text{PF}}_5$ and ${\text{PCl}}_5$ have five polar centers. Therefore, these substances are likely to be solid.

Conclusion

${\text{PF}}_5$ and ${\text{PCl}}_5$ are likely to be solid.