Which one of the following exhibits dipole-dipole attraction between molecules?

Question

Which one of the following exhibits dipole-dipole attraction between molecules? XeF_4 AsH_3 Co_2 BCI_3 CI_2 What types of intermolecular forces exist between PH_3 and N_2? dispersion forces and dipole-dipole forces dispersion forces and dipole-induced dipole forces dispersion forces and hydrogen bonds dispersion forces, hydrogen bonds, and induced dipole-induced dipole forces dispersion forces, hydrogen bonds, and dipole-induced dipole forces Of the following substances,  has the highest boiling point. H2O CO_2 CH_4 Kr NH_3 Which element is oxidized in the reaction below? Fe^+2 + H^_+ + Cr_2O_7^-2 rightarrow Fe^+3 + Cr^+3 + H_2O Fe Cr O H Which element is reduced in the reaction below ? I- + MnO_4- + H^+ rightarrow I_2 + MnO_2 + H_2O

Explanation / Answer

XeF4, Xenontetrafluoride is nonpolar. Hence Dipole-dipole attractions are not present between molecules. The intermolecular forces that occur between non- polar molecules are London dispersion forces.

AsH3 has trigonal pyramidal structure, just loke ammonia, due to the presence of lone pair of electrons on As. It is not a symmetric structure. Therefore it is polar.

What about the remaining molecules?

CO2 has linear structure, Hence it is non-polar, despite having polar C=O bonds. Polarity of one bond get cancelled by the other.

BCl3 has trigonal planar structrue. Hence net polarity is zero

Cl2 is a homonuclear diatomic molecule: molecule having one kind of atoms. hence it is non polar.

As stated before, the only intermolecular forces that occur between non- polar molecules are London dispersion forces.

Hence the correct option is (B) That is AsH3

2. Theoretically dispersion forces exist between molecules in all compounds. They are significant only in non-polar molecules as they are weak forces compared to other type of forces.

PH3 has  trigonal pyramidal structure, just loke ammonia and AsH3, due to the presence of lone pair of electrons on P. It is not a symmetric structure. Therefore it is polar.

N2 is a homonuclear diatomic molecule: molecule having one kind of atoms. hence it is non polar. A bond can be polar only when there is electronegativity difference. There cannot be electronegativity difference between two N atoms. Dipole- dipole interaction is possible when the molecule is polar. Hydrogen bonding occurs between H and electronegative elements like N,O and F.

PH3 being polar induces polarity in the neighbouring Nitrogen molecules.

Hence, the forces present between PH3 and N2 are dispersion forces and dipole-induced dipole forces.

Hence correct option is (B)

3. Boiling point depends upon intermolecular forces of attraction. Stronger the intermolecular forces higher is the boiling point. For instance if we compare B P of alcohol with water, water has higher B P. as the force of attraction present between water molecules is much stronger than that of alcohol molecules. CO2(linear) and CH4(tetrahedral) are non-polar molecules. Hence weak dispersion forces are present between molecules. Between Ar atoms again, weak dispersion forces are present. In ammonia, molecules are associated through H- bonding.

In water also molecules are associated through hydroge bonding.

However, O-H bond is more polar the N-H bond. Hence H- bonding in water is much stronger than in ammonia. Hence large amount of energy is required to break these bonds. Hence water has the highest B P among the given substance. Hence correct option is (1)

4. Fe+2  + Cr2O32-  + 14 H+ ---------- 2Cr+3  + Fe+3 + 7 H2O

Element is oxidised when it loses electrons and its oxidation number increases.

Element is reduced when it gains electrons and its oxidation number decreases.

Here, Oxidation state of iron is changing from +2 to +3. That is increase in oxidation number. which is possible only if it loses electrons, which is called oxidation.Thus iron is oxidised in this reaction. correct option is (A).

Oxidation state of Cr is changing from +6 in Cr2O32- to + 3 in Cr+3. thus it is reduces

5. I-  + MnO4-  + H+ --------- I2  + MnO2  + H2O

In this reaction Oxidation state of iodide ion is changing from -1 to zero in I2, that is increase in oxidation number.and Oxidation state of Mn is changing from +7 to +4, that is decrease in oxidation number. decrease in oxidation number is possible only when it accepts electrons. Thus it is reduced. Thus element Mn is reduced.

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.