Question

What are the condensed structural formulae for the following molecules
A. Methanoic acid
B. cis-But-2-ene
C. Cyclopentanol
D. 3-methylcyclohexene

Answer 1

Hint: A condensed structural formula is a system of representing organic structures in a line of text which shows all atoms but omits the vertical bonds and almost all the horizontal single bonds. When a group of atoms are bonded to a single atom in the compound, then parenthesis is used around the group along with the carbon atom to which it is bonded.

Complete answer:
The condensed structural formulae for each given molecule are as follows:
A. Methanoic acid: It is also known as formic acid and it is the simplest carboxylic acid with molecular formula $ C{O_2}{H_2} $ . The condensed structural formula of methanoic acid is $ HCOOH $ .
B. cis-But-2-ene: The molecular formula of butene is $ {C_4}{H_8} $ and in order to show its cis form, we need to all horizontal bonds within the structural formula. So, instead of representing it with condensed structural formula, it is preferred to represent the stereochemistry of the molecule with general structural formula which is as follows:

C. Cyclopentanol: The molecular formula of Cyclopentanol is $ {C_5}{H_{10}}O $ and because of the presence of a ring, we cannot represent the molecule in a condensed structural formula. The general structural formula of Cyclopentanol is as follows:

D. 3-methylcyclohexene: The molecular formula of 3-methylcyclohexene is $ {C_7}{H_{12}} $ and because of the presence of ring, we cannot represent the molecule in condensed structural formula. The general structural formula of 3-methylcyclohexene is as follows:

Note:
Remember that the structural formula is preferred over the molecular formula for representing organic compounds because in most of the cases a molecular formula does not uniquely represent a single compound but may represent a group of molecules having different structural formulae known as isomers.