Volume 1 (Issue 2)
Volume 2 (Issue 1) Download

Effect of concentration and temperature on viscosity of Ethanol measured using Ostwald Viscometer

C. Bhosale and M. Shah

 

Abstract

Viscosity is dependent on the intermolecular forces of attraction present. As the strength of the forces increases, so does the viscosity. The intermolecular forces of attractions in water and ethanol are hydrogen bonding and London forces. The water consists of polar hydroxyl groups that are hydrophilic which means they are attracted to water. These groups undergo strong hydrogen bonding. The ethanol molecule is able to hydrogen bond, and has a large amount of London forces. The ethanol molecule has a hydroxyl group as well as an alkyl group. The alkyl group is non-polar and hydrophobic [1]. It is repelled by water and thus is unable to make a hydrogen bond and instead participates in London forces. The type of forces of attraction that the two molecules exhibit is vital to understand and explain the trend in viscosity. Hydroxyl groups participate in hydrogen bonding with each other as they consist of the ?+ hydrogen atoms, along with the lone pair of electrons from the ?- oxygen atom. On the other hand, the alkyl groups form London forces, which are relatively much weaker forces of attraction, with the hydroxyl group as well as with each other. So, the hydroxyl-hydroxyl interactions are Hydrogen Bonded; alkyl-alkyl and alkyl-hydroxyl interactions form London forces.