Question

Identify the correct statements:

• (i) LiF has more covalent character compared to KF.
• (ii) Dipole moment of NF₃ is greater than that of NH₃.
• (iii) The bond order is same for F₂ and O₂.
• (iv) Ionic compounds possess low melting and boiling points.

• A. i, ii, iv only
• B. i, ii, iv, iii
• C. ii, iii, iv only
• D. i, iii only

Hint:

Covalent character increases with decreasing size of the ion, and dipole moment increases with the difference in electronegativity between bonded atoms.

Answer 1

The Correct Option is C

Step 1:
Analyze the statements:
- (i) Incorrect. LiF is more ionic than KF due to the smaller size of Li$^+$ and higher charge density.
- (ii) Correct. $\text{NF}_3$ has a higher dipole moment than $\text{NH}_3$ due to the electronegativity difference between nitrogen and fluorine.
- (iii) Correct. Both $\text{F}_2$ and $\text{O}_2$ have bond order 1 according to Molecular Orbital Theory.
- (iv) Correct. Ionic compounds typically have higher melting and boiling points due to strong electrostatic forces between ions. However, this statement is misleading, as ionic compounds generally have high melting points, but this is a general trend. Thus, the correct answer is option (3).