Question

Indicate which reactions are redox reactions.

Check all that apply.

AgNO3(aq)+KI(aq)→AgI(s)+KNO3(aq)

Zn(s)+Cu2+(aq)→Zn2+(aq)+Cu(s)

S(s)+O2(g)→SO2(g)

2Na(s)+I2(g)→2NaI(s)

Answer 1

Reduction = species that GAINS electrons

Oxidation = process in which a specie will LOSS electrons

Reducing agent = The species that favors reduction, i.e. it will oxidize in order to reduce another species

Oxidizing agent = The species that favors oxidation, i.e. it will reduce in order to oxidise another species

then...

a)

Ag remains with + 1

NO3 remains with -1

K = +1, I= -1

no redox, this is preciptiation only

b)

this is redox

Zn goes from 0 in ZN(S) to +2

Cu goes from +2 to 0

c)

S goes from 0 to +4

O goes from 0 to -2

this must be redox

d)

Na goes from 0 to +1

I2 goes from 0 to -1

this is redox

therefore, only a is not redox, all other are redox