Question

Consider three generic acids: HX , HY , and HZ . The number of H plus and X minus ions in solution is equal to the initial number of HX molecules added to the solution. One quarter of the HZ molecules form H plus and Z minus ions in solution. The other three quarters of the molecules remain as HZ in solution. One half of the HY molecules form H plus and Y minus ions in solution. The other half of the molecules remain as HY in solution. Arrange the acids according to strength. Strongest acid Weakest acid Answer Bank

Answer 1

Answer: The strongest acid is HX, while the weakest is HZ.

Explanation: When we add water to an acid, the acid dissolves and dissociates. The reaction is: $HA_{aq}$ ⇒ $H^{+} + A^{-}$. If it completely dissociates, it is a strong acid. If not, is a weak acid.

For HX, the question says the number of H and X is equal to the initial number HX, which means that all the $H^{+}$ dissociated. Thus, HX is a strong acid.

For HY, a half of molecules form ions, in other words, not all is dissociated, so HY is a weak acid.

For HZ, only a quarter of molecules form ions, so not all is dissociated, thus another weak acid.

Comparing HZ and HY, HZ is the weakest acid, since less molecules dissociated in water.

Arraging the acids from strongest to weakest will be HX, HY and HZ.

Answer 2

Answer:

Stongest Acid to Weakest Acid (↓)

HX

HY

HZ

Explanation:

"The strongest acid contains most ions and lesser undissociated molecules in a solution."

Here, HX is the strongest acid because all the HX molecules have been dissociated into ions. Hence, no undissociated molecule is present in HX anymore.

While HY contains half ions and half molecules and HZ contains a lesser number of ions than HY in a solution making it the weakest acid.