Which of the following liquids would have the highest viscosity at 25degC

A) CH3OCH3, B) CH3CL2, C) C2H5OH, D) CH3Br E) HOCH2CH2OH

Ethylene glycol

HOCH₂CH₂OH

Explanation:

For the molecules in the question, the viscosity will rise with the number of hydrogen bonds that can be formed.

A hydrogen bond is a week physical bond which is formed when hydrogen is found between atoms with high electronegativity (oxygen, nitrogen, fluorine):

O-H ··· O, N-H ··· O, N-H ··· O, O-H ··· N, F-H ··· F and so on.

Here we have have two compounds that can form hydrogen bonds (between themselves):

C) ethanol and D) ethylene glycol

Ethylene glycol have more hydroxide groups (-OH) than the ethanol so it will form more hydrogen bonds thus increasing its viscosity.