Pertanyaan
Titik didih senyawa NH_(3),H_(2)O dan HF yang terbentuk melalui ikatan kovalen polar lebih tinggi dibandingkan dengan molekul lain yang juga berikatan kovalen polar. Hal ini disebabkan karena adanya A. Gaya Van der Walls (dipol-dipol) B. Ikatan hydrogen C. Gaya dispersi D. Gaya London E. Dipol sesaat
Solusi
Jawaban
B
Penjelasan
The question pertains to the boiling points of NH3 (ammonia), H2O (water), and HF (hydrogen fluoride), which are higher than those of other molecules with polar covalent bonds. The key factor influencing the boiling points of these molecules is the type of intermolecular forces they exhibit.A. Gaya Van der Waals (dipol-dipol): Van der Waals forces include dipole-dipole interactions, which occur between polar molecules. However, these are not the strongest intermolecular forces present in NH3, H2O, and HF.B. Ikatan hydrogen (Hydrogen bonding): Hydrogen bonds are a type of dipole-dipole interaction but are particularly strong. They occur when a hydrogen atom is bonded to a highly electronegative atom (like nitrogen, oxygen, or fluorine) and is attracted to another electronegative atom in a different molecule. NH3, H2O, and HF all exhibit hydrogen bonding, which is much stronger than ordinary dipole-dipole interactions. This hydrogen bonding is responsible for their higher boiling points compared to other polar covalent molecules.C. Gaya dispersi (Dispersion forces): Dispersion forces are the weakest intermolecular force and are present in all molecules, whether polar or nonpolar. They are not the primary reason for the high boiling points of NH3, H2O, and HF.D. Gaya London (London forces): London forces are a type of dispersion force and, like dispersion forces, are not the primary reason for the high boiling points of NH3, H2O, and HF.E. Dipol sesaat (Instantaneous dipole): This refers to temporary dipoles that occur due to momentary uneven distribution of electrons in a molecule. These are also a type of dispersion force and are not the main reason for the high boiling points of NH3, H2O, and HF.Therefore, the correct answer is hydrogen bonding, which is significantly stronger than other types of van der Waals forces and is the primary reason for the higher boiling points of NH3, H2O, and HF compared to other molecules with polar covalent bonds.