1) Answer is: D. both B and C.
Activated complex is collection of intermediate structures in a chemical reaction that forms while bonds are breaking and new bonds are forming.
The transition state is the configuration at the peak of the diagram while the activated complex can refer to any point near the maximum.
Activation energy is the minimum energy colliding particles must have in order to react.
2) Answer is: B. chemical equilibrium.
Balanced chemical reaction: A + B ⇄ C + D.
1) In a chemical reaction, chemical equilibrium is the state in which both reactants ( and BA) and products (C and D) are present in concentrations which have no further tendency to change with time.
2) At equilibrium, both the forward and reverse reactions are still occurring.
3) Reaction rates of the forward and backward reactions are equal and there are no changes in the concentrations of the reactants and products.
3) Answer is: C. inhibitor.
Inhibitor is a substance that decreases the rate of a chemical reaction.
Inhibitor can reduce the effectiveness of a catalyst in a catalysed reaction.
Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst.
Reactions occur faster with a catalyst because they require less activation energy.
4) Answer is: A. Fe.
Balanced reaction: Fe + 2HCl → FeCl₂ + H₂.
Oxidation reaction: Fe⁰ → Fe⁺² + 2e⁻.
Reduction reaction: 2H⁺ + 2e⁻ → H₂⁰.
Reducing agent is an element or compound that loses an electron to another chemical species in a redox chemical reaction and they have been oxidized.
Iron (Fe) change oxidation number from 0 to +2 (lose electrons), iron is oxidized (reducing agent).