Question

A) How does a polar covalent bond differ from a non-polar covalent bond?

B. ) In a single molecule of water, what is the type of bond between the two hydrogen atoms and the oxygen atom?

Answer 1

A) Answer-

Polar covalent bond : In Polar covalent bond unequal sharing of electrons between two atoms occur i.e., the two atoms pull the electrons unequally. The atom which is more electronegative will pull the electron harder and as a result that atom acquire a slight negative charge ; the atom which is less electronegative will pull the electron less and as a result acquire a slight positive charge.
Example: In HCl we can see the polar covalent bond between H and Cl atom. Chlorine (Cl) is more electronegative so it acquire slightly negative charge and on the other hand hydrogen atom acquire slightly positive charge.

Non polar covalent bond: In non polar covalent bond equal sharing of electrons between two atoms occur i.e., the two atoms pull electrons equally. Here is no difference in electronegative between two atoms.
Example: Cl2 is a good example where we can see non polar covalent bond. Here two atoms are both chlorine atoms and they obviously have same electronegative. Thus the sharing of electrons is equal.

So from the above discussion we can say that the main difference between polar and nonpolar covalent bond is that in the polar covalent bond the sharing of electron is unqual as a result have two poles with different charge i.e., one pole slightly positive and the other slightly negative; and in non polar covalent bond the electrons are shared equally so no polarity occurs (no difference of charge between atoms).

B) Answer- In a single molecule of water, there occurs polar covalent bond between hydrogen and oxygen atom. Oxygen makes polar covalent bond with each of the two hydrogen atoms.
Explanation: Oxygen molecule is more electronegative that hydrogen so it draws the electron density closer to itself giving it a slightly negative charge. In turn the charge of two hydrogen atoms become slightly positive.