A precipitation reaction 2. A Lewis acid-base reaction the produces a coordination complex: A Lewis acid-base reaction the produces a coordination complex 3. An oxidation-reduction reaction that is also a synthesis reaction: An oxidation-reduction reaction that is also a synthesis reaction Column B a. Pb2 (aq0 CrO42-(aq) --> PbCrO4(s) b. 2 Mg(s) O2(g) -> 2 MgO(s) c. Ag (aq) 2NH3(aq) --> [Ag(NH3)2] (aq)

Pb2+ (aq) + CrO42-(aq) --> PbCrO4(s) - A precipitation reaction

2 Mg(s) + O2(g) -> 2 MgO(s) - An oxidation-reduction reaction that is also a synthesis reaction

Ag^+ (aq) + 2NH3(aq) --> [Ag(NH3)2]^+ (aq) - A Lewis acid-base reaction the produces a coordination complex

Explanation:

A precipitation reaction is one in which two aqueous reactants yields an insoluble product called a precipitate as shown in reaction 1 above.

In the second reaction Mg is oxidized from zero to + 2 while oxygen was reduced from zero to -2 as the MgO is formed hence the reaction is an oxidation-reduction reaction that is also a synthesis reaction.

In the third reaction, Ag^+ a Lewis acid reacts with NH3, a lewis base to yield the complex [Ag(NH3)2]^+.

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.

answersilicon (si); oxygen (o);