Given the following compounds: H2, HBr, HCl, HF

Question

A. Which will form an ionic bond?
B. Which will form a nonpooar covalent bond?
C. Which will form a polar covalent bond?

Answer 1

A. HBr and HCl
B, H2
C. HF
BUT you REALLY need to understand why.

Answer 2

None will form ionic bonds as a metal + nonmetal are required to generate the ionic compound. HF, HCl & HBr are polar covalent molecules with HF having the higher polarity followed by HCl and lastly HBr. However, it's interesting to note that (if in aqueous medium) the trend in acidity for this set of acids finds the HBr as the stronger acid followed by HCl, then HF as the weakest of the three. HF is actually a weak acid (Ka = 6.6E-4) in this set whereas HCl and HBr are strong acids (Ka = Infinity => 100% ionized). The reason is 'ionic radii' govern the ionization potential for the groups periodic trend and not electronegativity which is a series periodic trend. This, FYI, is known as the 'Hydrogen-Halide Paradox'. H₂(g) is the lone non-polar covalent structure.

Answer 3

Certainly it is true that gaseous HCl and gaseous HBr are polar covalent; however, aqueous solution of both are ionic.

Answer 4

Identify which of the following compound are formed by covalent bonds
1.HBr
2.CCl4
3.CH4

Answer 5

Convalent bond