Given the electronegativities below, which covalent single bond is most polar? element: h c n o electronegativity: 2.1 2.5 3.0 3.5

The choices present in this question are:
a) N-H      b) O-C     c) O-N     d) C-H     e) O-H

The values of electronegativity given:
H = 2.1     C = 2.5   N = 3.0    O = 3.5

To determine the most polar bond we calculate the electronegativity difference in each bond and determine the highest value:
a) N-H = 3.0 - 2.1 = 0.9
b) O-C = 3.5 - 2.5 = 1
c) O-N = 3.5 - 3 = 0.5
d) C-H = 2.5 - 2.1 = 0.4
e) O-H = 3.5 - 2.1 = 1.4
So the correct answer is e) O-H
 

The higher difference in the electronegativity has been in the O-H bond, the most polar bond is O-H.

The polarity of the bond can be defined as the difference in electronegativity.

For N-H bond:

Electronegativity of N - Electronegativity of H

= 3 - 2.1

= 0.9

For O-C bond:

Electronegativity of O - Electronegativity of C

= 3.5 - 2.5

= 1

For O-N bond:

Electronegativity of O - Electronegativity of N

= 3.5 - 3

= 0.5

For C-H bond:

Electronegativity of C - Electronegativity of H

= 2.5 - 2.1

= 0.4

For O-H bond:

Electronegativity of O - Electronegativity of H

= 3.5 - 2.1

= 1.4

Since the higher difference in the electronegativity has been in the O-H bond, the most polar bond is O-H.

For more information about the polar bonds, refer to the link:

link

Here is the link to the all information u need i mean answer key

Yeah, but what are you trying to ask?