Final answer:
The molecular formula for 1-bromo-3-pentyne is C₅H₇Br, taking into account the five carbons in the alkyne and the presence of a bromine atom.
Step-by-step explanation:
The student asked for the correct molecular formula for 1-bromo-3-pentyne. The molecule in question includes a bromine atom and a triple bond in a carbon chain. The correct formula must account for a five-carbon alkyne (which is an indication of a triple bond) with a bromine substituent. The molecular formula for this compound corresponds to the option where there are five carbons, at least one triple bond, and the presence of a bromine atom. Thus, the correct molecular formula for 1-bromo-3-pentyne is C₅H₇Br, which corresponds to option C).