Test: Acid Base & Redox Reactions - Chemistry MCQ

In a redox (oxidation-reduction) reaction, electrons are transferred between reactants, leading to changes in oxidation states.

The reaction CaCO3 ? CaO + CO2 is not a redox reaction because there is no transfer of electrons between the reactants.

Displacement reactions involve the replacement of an atom or ion in a compound by another atom or ion.

The species undergoing oxidation acts as a reducing agent. A reducing agent (also called a reductant or reducer) is an element or compound that loses (or "donates") an electron to another chemical species in a redox chemical reaction.

In this reaction, zinc (Zn) acts as the reducing agent as it donates electrons to copper ions.

Na₂S₂O₃  is act as an strong reducing agent. 

The balanced redox equation in a basic medium is: 2P4 + 16OH- + 8H2O2 ? 8PH3 + 8H2PO2-

In a non-metal displacement reaction, hydrogen is often displaced.

In this reaction, oxygen gas is reduced from a neutral state to an oxidation state of -2, while hydrogen ions are reduced from an oxidation state of +1 to a neutral state. The overall reaction is a redox reaction, in which hydrogen is oxidized and oxygen is reduced.