What type(s) of intermolecular forces exist between the following pairs: (a) HBr and H2S, (b) Cl2 and CBr4, (c) I2 and nitrate; (d) NH3 and CsHo: a) Dipole-dipole in addition to dispersion b) Induced dipole-induced dipole c) Ion-induced dipole in addition to dispersion d) Submission question
The Correct Answer and Explanation is:
✅ Correct interaction: Induced dipole–dipole
Final Answer:
✅ Option (a): Dipole-dipole in addition to dispersion
This choice correctly corresponds to pair (a) — HBr and H₂S — which are both polar molecules capable of dipole–dipole interactions along with dispersion forces.
Explanation Summary
Intermolecular forces are attractions between molecules that affect physical properties such as boiling points and solubility. These forces vary based on molecular polarity, presence of ions, and size.
In pair (a), HBr and H₂S are both polar molecules. Their intermolecular attraction involves dipole–dipole forces, which occur when positive and negative ends of polar molecules attract. Additionally, London dispersion forces exist universally due to temporary electron fluctuations. Hence, both dipole–dipole and dispersion forces are present.
In pair (b), Cl₂ and CBr₄ are nonpolar. Nonpolar molecules cannot form dipole–dipole attractions. However, temporary distortions in electron clouds lead to induced dipole–induced dipole (London dispersion) forces, which are relatively weak but significant in large atoms or molecules like CBr₄.
Pair (c) involves I₂ (nonpolar) and nitrate ion (charged). When an ion like NO₃⁻ approaches I₂, it can distort its electron cloud, leading to ion–induced dipole interactions. Dispersion forces are also always present, making this a combination of ion-induced dipole and dispersion forces.
In pair (d), NH₃ is polar and can induce a dipole in benzene (nonpolar). The result is an induced dipole–dipole interaction, as benzene’s electron cloud is temporarily distorted by NH₃’s dipole.
Thus, the correct identification of interactions shows that option (a) best matches pair (a), making it the correct answer.
