Which of the following exhibits ion-dipole forces?
1) KBr(s)
2) NaF(aq)
3) Ag(s)
4) Cl2(g)
KBr
Ion-dipole forces occur between an ion and a polar molecule. A polar molecule has a positive and negative end due to an uneven distribution of electron density.
In this case, option 2) NaF(aq) exhibits ion-dipole forces. NaF is an ionic compound where Na+ is the cation and F- is the anion. When NaF dissolves in water (represented by "(aq)"), the polar water molecules (H2O) surround the Na+ and F- ions. The positive end of the water molecule (H) interacts with the negatively charged F- ion, forming an ion-dipole force. Similarly, the negative end of the water molecule (O) interacts with the positively charged Na+ ion, creating another ion-dipole force.
Therefore, the correct answer is option 2) NaF(aq).
To determine which of the following exhibits ion-dipole forces, we need to understand what ion-dipole forces are and how they arise.
Ion-dipole forces occur between an ion and a polar molecule. The positive or negative charge of an ion attracts the partially negative or positive end of a polar molecule. This electrostatic attraction creates the ion-dipole force.
Now, let's analyze each substance to see if it exhibits ion-dipole forces:
1) KBr(s): This substance is in the solid state, meaning that the ions are tightly packed and not mobile. Therefore, ion-dipole forces do not play a significant role in the solid phase.
2) NaF(aq): In this case, NaF is dissolved in water to form an aqueous solution. Water (H2O) is a polar molecule due to its bent molecular structure and electronegativity difference between oxygen and hydrogen. NaF dissociates into Na+ and F- ions when dissolved in water. These ions can form ion-dipole forces with the polar water molecules. Therefore, NaF(aq) exhibits ion-dipole forces.
3) Ag(s): Silver (Ag) is an elemental solid. It consists of metal ions held together by metallic bonds, which are not classified as ion-dipole forces.
4) Cl2(g): Chlorine gas (Cl2) consists of two non-metal atoms bonded together by a covalent bond. It does not contain ions or a polar structure. Therefore, Cl2(g) does not exhibit ion-dipole forces.
So, out of the options provided, only NaF(aq) exhibits ion-dipole forces.