Question

What is the condensed structural formula for ethyne?

Answer 1

Hint: Ethyne is a type of alkyne that consists of triple bonds with two carbon atoms. The condensed structural formula is different from the structural formula. Structural formula tells the bonds and the structure of atoms, while a condensed structural formula represents the exact number of atoms of a molecule written in the way of chemical formula but along with representation of bond type.

Complete answer:
The condensed formula is the representation of all the atoms present in any molecule in the form of a general formula, without showing bonds. The condensed formulas of molecules are convenient to study and easy to write in compact spaces. The condensed structural formula is different from the chemical or molecular formula, for it has the atoms written beside the atoms according to their positions with the representation of double or triple bonds as in the structural formula, while molecular formula tells the total atoms present in the molecule without telling us the positions of atoms.
Ethyne is one of the alkynes that have a triple bond. Ethyne consists of 2 carbon atoms. The general formula of ethynes is ${{C}_{n}}{{H}_{2n-2}}$ , where n is the number of carbons. So, according to this, the general formula of ethyne will be, ${{C}_{2}}{{H}_{2}}$ . Now, we know that it has 2 hydrogen, so we can write its condensed structural formula as,
$HC\equiv CH$
The condensed structural formula shows the presence of the triple bond between both the carbons along with hydrogen attached with them.
Hence, the condensed structural formula for ethyne is $HC\equiv CH$.

Note:
A structural formula shows the placing of bonds in a molecule which is drawn in a manner of the atoms grouped together. While the molecular formula represents total atoms in a compound, example, molecular formula for ethanol is ${{C}_{2}}{{H}_{6}}O$ , while its condensed formula will be, $C{{H}_{3}}C{{H}_{2}}OH$ .