It is a common observation that many compounds containing hydrogen attached to highly electronegative elements such as oxygen, nitrogen, or fluorine, often exhibit unexpected properties, such as relatively high melting points, boiling points, viscosity, solubility in water etc Such an unexpected behaviour can be explained on the basis of hydrogen bonding. When a hydrogen atom is attached to a highly electronegative element of small size such as F. N, 0. etc. the electronegative atoms strongly attracts the shared pair of electrons towards it self. As a result, the hydrogen atom becomes slightly positive and the electronegative element becomes slightly negative when two molecules of such a substance say HF come close to each other, the negatively charged fluorine atom of one molecule attracts the positively charged hydrogen atom of the other molecule. A hydrogen atom, thus links to highly electronegative atoms, one by a strong covalent bond and the other by weak electrostatic attraction as shown ahead `overset(delta+)H-overset(delta-)F....overset(delta+)H-overset(delta-)F`, the dotted line represents a hydrogen bond.
Which is most viscous ?
A. `CH_3OH`
B. `C_2H_5OH`
C. `undersetunderset(CH_2OH)(|)(C )H_2OH`
D. None
