2.
Which statement is true for the following chemical reactions?
CuCO3 + heat à CuO + CO2
CuO + SnO à Cu + SnO2
a. CO2 is oxidized and SnO2 is reduced
b. CuCO3 is oxidized and CuO is reduced
c. CuO is oxidized and SnO is reduced
d. SnO is oxidized and CuO is reduced

CuCO3 Decomposition and CuO + SnO Redox Reaction: Correct Answer Analysis

The correct statement is option d: SnO is oxidized and CuO is reduced. This holds true for the second reaction where tin(II) oxide loses electrons while copper(II) oxide gains them.​

Reaction Breakdown

The first reaction, CuCO₃ → CuO + CO₂ upon heating, is a thermal decomposition with no redox change. Copper remains at +2 oxidation state in both CuCO₃ and CuO, while CO₃²⁻ breaks to CO₂ (C at +4).​​

The key redox occurs in CuO + SnO → Cu + SnO₂. Copper reduces from +2 in CuO to 0 in Cu, while tin oxidizes from +2 in SnO to +4 in SnO₂.​

Option Analysis

• a. CO₂ is oxidized and SnO₂ is reduced: False. CO₂ forms in the first non-redox reaction (C unchanged at +4); SnO₂ is the oxidized product.​

• b. CuCO₃ is oxidized and CuO is reduced: False. No oxidation state change for Cu (+2 to +2); it’s decomposition.​

• c. CuO is oxidized and SnO is reduced: False. CuO reduces (Cu +2→0); SnO oxidizes (Sn +2→+4).​​

• d. SnO is oxidized and CuO is reduced: True. Matches electron transfer: Sn loses 2e⁻, Cu gains 2e⁻.​

In CuO SnO redox reaction oxidation reduction, understanding electron transfer is crucial for exams like CSIR NET Life Sciences. The reactions CuCO₃ + heat → CuO + CO₂ (thermal decomposition, no redox) and CuO + SnO → Cu + SnO₂ (disproportionation-like redox) test oxidation state analysis.​

Oxidation States Table

CuO SnO redox reaction oxidation reduction confirms option d as correct: SnO (reducing agent) oxidizes to SnO₂, CuO (oxidizing agent) reduces to Cu. This aligns with standard inorganic chemistry principles.​