Acetic acid, the first molecule in carboxylic acid series has –CH3 group and shows unique property of solubility in aqueous solutions. Number of workers already reported that these acids make dimer or higher aggregation in aqueous solutions. To understand the volume properties, densities (ρ), are measured for acetic acid in water at 298.15 K. Values of experimental densities were used to calculate derived properties like apparent molal volumes(ϕv), apparent molal volumes at infinite dilution(ϕᵒ v), limiting apparent molal volume (V2 ), volume of ionisation(DV° ), volume of dimers ( o v2 f ) and volume change due to dimerisation ( D DV° ). To understand solute-solute interaction, molecular dynamic (MD) simulation was performed for acetic acid in water at T=298.15K. It is reported that acetic acid prefers chain dimer in aqueous solution and the results are supported by the aggregation of acetate ions in simulation ensemble