Given the equations A, B, C, and D:

(A) AgNO3 + NaCl → AgCl + NaNO3
(B) Cl2 + H2O → HClO + HCl
(C) CuO + CO → CO2 + Cu
(D) NaOH + HCl → NaCl + H2O

Which two equations represent redox reactions?

B and C

Explanation:

(A) AgNO₃ + NaCl → AgCl + NaNO₃

This is a double displacement reaction. It is not a redox reaction because the elements have the same oxidation numbers on both sides.

(B) Cl₂ + H₂O → HClO + HCl

This is a redox reaction.

Cl₂ is oxidized to HClO. The oxidation number of Cl increases from 0 to +1.

Cl₂ is reduced to HCl. The oxidation number of Cl decreases from 0 to -1.

(C) CuO + CO → CO₂ + Cu

This is a redox reaction.

CO is oxidized to CO₂. The oxidation number of C increases from +2 to +4.

CuO is reduced to Cu. The oxidation number of Cu decreases from +2 to 0.

(D) NaOH + HCl → NaCl + H₂O

This is a double displacement reaction. It is not a redox reaction because the elements have the same oxidation numbers on both sides.

- "the choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."

10 years is the answer