Final answer:
In decreasing order of acidity, the compounds rank as follows: sulfuric acid (most acidic), acetic acid, 2-chloroethanol, water, ethanol, hex-1-yne, tert-butyl alcohol, ammonia, and hexane (least acidic). Factors like electronegativity, ability to stabilize the conjugate base, and bond strength of H-A bonds were considered. (Sulfuric acid > Acetic acid > 2-Chloroethanol > Water > Ethanol > Hex-1-yne > tert-Butyl alcohol > Ammonia > Hexane).
Step-by-step explanation:
To rank the compounds in decreasing order of acidity, we need to consider factors such as the presence of electronegative atoms which can stabilize the negative charge on the conjugate base, the ability to donate a proton, and the strength of the H-A bond in binary hydrogen compounds.
- Sulfuric acid (H₂SO₄) is a strong acid and is at the top of the list.
- Acetic acid (CH₃COOH) is a weaker acid than sulfuric acid but stronger than other organic acids listed here.
- 2-Chloroethanol (ClCH₂CH₂OH) is more acidic than ethanol due to the electron-withdrawing effect of the chlorine atom which stabilizes the conjugate base.
- Water (H₂O) has a pKa of around 15.7, making it more acidic than alcohols and ammonia but less acidic than acetic acid or sulfuric acid.
- Ethanol (CH₃CH₂OH) is slightly more acidic than tert-butyl alcohol due to less steric hindrance around the hydroxyl group.
- Hex-1-yne (CH₃C≥CCH₂CH₂CH₃) is an alkyne and has sp-hybridized carbons, which hold the hydrogen more tightly, therefore slightly less acidic.
- tert-Butyl alcohol ((CH₃)₃COH) is less acidic because of the steric hindrance that hinders proton removal.
- Ammonia (NH₃) is a weak acid and more of a base compared to the other listed compounds.
- Hexane (CH₃(CH₂)4CH₃) is practically non-acidic as alkanes do not readily donate protons.
The order of decreasing acidity is: Sulfuric acid > Acetic acid > 2-Chloroethanol > Water > Ethanol > Hex-1-yne > tert-Butyl alcohol > Ammonia > Hexane.