Question

Which reactions are oxidation-reduction reactions? Check all that apply.

A) 2NaCl₂ + Cl₂ → 2NaCl
B) Pb(OH)₂ → PbO + H₂O
C) Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag
D) ZnBr₂ + 2AgNO₃ → 2AgBr + Zn(NO₃)₂
E) CH₄ + 2O₂ → CO₂ + H₂O

Answer 1

Oxidation-reduction reactions are identified by a change in oxidation states of elements involved. Among the listed reactions, options C, D, and E are redox reactions, as they involve the transfer of electrons leading to changes in oxidation states.

Step-by-step explanation:

The oxidation-reduction (redox) reactions among the given options are:

• C) Cu + 2AgNO₃ → Cu (NO₃) ₂ + 2Ag: Copper (Cu) is oxidized as it goes from 0 to +2 oxidation state and silver (Ag) is reduced from +1 to 0 oxidation state.
• D) ZnBr₂ + 2AgNO₃ → 2AgBr + Zn (NO₃) ₂: Zinc (Zn) is oxidized from +2 to +4 oxidation state, and silver (Ag) is reduced.
• E) CH₄ + 2O₂ → CO₂ + H₂O: In this combustion reaction, carbon (C) is oxidized from -4 to +4 oxidation state, and oxygen (O) is reduced.

The reactions B) Pb (OH)₂ → PbO + H₂O, and A) 2NaCl₂ + Cl₂ → 2NaCl do not involve changes in the oxidation states of the elements; hence they are not redox reactions.