Which pair of moecules will have permanent dipole moment for both members ?

Options

A. `NO_(2) and CO_(2)`
B. `NO_(2) and O_(3)`
C. `SiF_(4) and CO_(2)`
D. `SiF_(4) and NO_(2)`

Explanation

To determine which pair of molecules will have a permanent dipole moment for both members, we need to analyze the molecular structures and their dipole moments. Let's go through the options step by step.

### Step 1: Analyze NO2 and CO2
1. **Structure of NO2**: Nitrogen dioxide (NO2) has a bent structure due to the presence of one unpaired electron on nitrogen. The dipole moments from the N=O bonds do not cancel out, resulting in a net dipole moment.
2. **Structure of CO2**: Carbon dioxide (CO2) has a linear structure. The dipole moments from the C=O bonds are equal in magnitude but opposite in direction, leading to a net dipole moment of zero.

**Conclusion**: NO2 has a permanent dipole moment, while CO2 does not. Thus, this pair does not satisfy the condition.

### Step 2: Analyze NO2 and O3
1. **Structure of O3**: Ozone (O3) has a bent structure with a resonance hybrid form. The dipole moments from the O=O bonds and the lone pair on the central oxygen do not cancel out, resulting in a net dipole moment.
2. **NO2**: As previously analyzed, NO2 has a permanent dipole moment.

**Conclusion**: Both NO2 and O3 have permanent dipole moments. This pair satisfies the condition.

### Step 3: Analyze SiF4 and CO2
1. **Structure of SiF4**: Silicon tetrafluoride (SiF4) has a tetrahedral structure, which is symmetric. The dipole moments from the Si-F bonds cancel out, resulting in a net dipole moment of zero.
2. **CO2**: As previously analyzed, CO2 also has a net dipole moment of zero.

**Conclusion**: Neither SiF4 nor CO2 has a permanent dipole moment. This pair does not satisfy the condition.

### Step 4: Analyze SiF4 and NO2
1. **SiF4**: As previously analyzed, SiF4 has a net dipole moment of zero due to its symmetric tetrahedral structure.
2. **NO2**: As previously analyzed, NO2 has a permanent dipole moment.

**Conclusion**: SiF4 does not have a permanent dipole moment, while NO2 does. This pair does not satisfy the condition.

### Final Conclusion
The only pair of molecules that have a permanent dipole moment for both members is **NO2 and O3**.

### Answer
**The pair of molecules that will have a permanent dipole moment for both members is NO2 and O3.**

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