Final answer:
The conjugate base of the acid HC≡CH is C≡C-, with the carbon that lost the hydrogen holding a lone pair of electrons and a negative charge.
Step-by-step explanation:
To draw the conjugate base for the acid HC≡CH (acetylene or ethyne), you would remove a proton (H+) from the molecule. The resulting conjugate base would be C≡C- with a lone pair of electrons on the carbon that lost the hydrogen. Both carbon atoms are still connected by a triple bond. Here is the structural representation:
H-C≡C: -
It is important to remember that the negative charge represents the additional lone pair of electrons that remains after the hydrogen ion is removed.
In acid-base chemistry, identifying conjugate acid-base pairs is crucial. When an acid donates a proton, the remaining species is its conjugate base. This concept is central to the Brønsted-Lowry Acid-Base Theory, which defines acids and bases according to their ability to donate or accept protons (H+).