Consider the chemical equation below.

mg(oh)2 + 2hno3 --> mg(no3)2 + 2h2o

which is the net ionic equation? (b. is already incorrect.)

a. h^+ + oh^- --> h2o
c. mg^+2 + 2no3^- --> mg^+2 + 2h2o
d. mg^+2 + 2oh^- + 2h^+ + 2no3^- --> mg^+2 + 2no3^- + 2h2o

Answer is: A. H⁺ + OH⁻ → H₂O.

Balanced chemical reaction:

Mg(OH)₂ + 2HNO₃ → Mg(NO₃)₂ + 2H₂O.

Ionic reaction:

Mg²⁺ + 2OH⁻ + 2H⁺ + 2NO₃⁻ → Mg²⁺ + 2NO₃⁻ + 2H₂O.

Cancel all species that appear on both sides of the equation to get net ionic reaction.

Net ionic reaction: 2OH⁻ + 2H⁺ → 2H₂O or OH⁻ + H⁺ → H₂O;

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.