Question

Match the chemical bond with its best description

Bonds in a CH3OH methanol molecule

      [ Choose ]            hydrogen            covalent            ionic      

Bonds in a NaCl (salt) molecule

      [ Choose ]            hydrogen            covalent            ionic      

Bond between O and H in a KOH (potassium hydroxide) molecule

      [ Choose ]            hydrogen            covalent            ionic      

Bonds organizing alpha helices of proteins

      [ Choose ]            hydrogen            covalent            ionic      

Bonds between water molecules in solid ice

      [ Choose ]            hydrogen            covalent            ionic      

Answer 1

1) Methanol(CH3OH) contains oxygen, which is highly electronegative atom attached directly to hydrogen. Thus, it shows hydrogen bonding. It is not an ionic compound but it is a polar compound and exhibit dipole dipole interactions. Methanol doesn't contain covalent bond because there is no sharing of electrons during bonding.

Thus answer for methanol is hydrogen.

2) NaCl contains two oppositely charged ions which are Na+(cation) and Cl-(anion). The bond formation takes place due to attraction between these two opposite charges. Thus, they contain ionic bonds. There is complete transference of electrons from Na to Cl that's why Cl gets negatively charged and Na remains positively charged.

There is no hydrogen bonding and no covalent bond.

Thus. answer for NaCl is ionic.

3) KOH contains covalent bond between O and H, whereas there is ionic bond between K and O.

O and H contains 6 and 2 electrons respectively, thus there is sharing of electrons leading to covalent bond. K and O makes bond by transfer of electrons from K to O leading to ionic bond.

Hydrogen bond is not possible due to absence of hydrogen.

Thus, for KOH, answer can be covalent and ionic both.

4) There is hydrogen bond in alpha helix of protein. Every N-H group makes hydrogen bond with C=O group in protein sequence.

5) In solid ice, there is cage like structure of water molecules one after another. Hydrogen of one water molecule makes hydrogen bond with oxygen of other water molecule. Thus, there is hydrogen bonding in solid ice.