Question

#1. The arrangement of atoms at the peak of the activation energy barrier is known as the _____. A. activation rate B. activated complex C. transition state D. both B and C #2. Two opposing reactions (A + B C + D) occurring simultaneously at the same rate is an example of:
A. reversibility./B. chemical equilibrium./C. neither a nor b/D. both a and b
#3. A substance that interferes with the action of a catalyst is known as a(n) _____.

A. negative inhibitor
/B. either an inhibitor or negative inhibitor /C. inhibitor /D. activated complex
#4. The reducing agent in the reaction described in Fe + 2HCl → FeCl2 + H2 is


A. Fe./B. HCl./C. FeCl2.

Answer 1

Answer :

1) The correct option is, (D) both B and C.

2) The correct option is, (D) both A and B

3) The correct option is, (C) inhibitor.

4) The correct option is, (A) Fe

Explanation :

For part 1 :

Activated complex or transition state : It is the state where the bonds are loosened and new lose bonds are formed between them. It is unstable state and immediately dissociates to form the stable products. The arrangement of atoms takes place at the peak of the activation energy barrier.

For part 2 :

The balanced chemical reaction is,

$A+B\rightleftharpoons C+D$

Chemical equilibrium : It is defined as a state where the rate of forward reaction is equal to the rate of backward reaction. That means there is no net change in the concentration of the reactants and the products.

Reversibility : It is defined as, in a reversible reaction when reactant A and B react to form products C and D and in the reverse reaction, C and D react to form A and B. That means process is reversible.

For part 3 :

Inhibitor : It is the substance that decreases the rate of the chemical reaction. It can reduce the effectiveness of the catalyst in a catalyzed reaction.

Or we can say that it is a substance that interferes with the action of a catalyst.

For part 4 :

The balanced redox reaction is :

$Fe+2HCl\rightarrow FeCl_2+H_2$

The half oxidation-reduction reactions are:

Oxidation reaction : $Fe\rightarrow Fe^{2+}+2e^-$

Reduction reaction : $2H^++2e^-\rightarrow H_2$

From this we conclude that the 'Fe' is the reducing agent that loses an electron to another chemical species in a redox chemical reaction and itself oxidized.

Hence, the reducing agent is, Fe

Answer 2

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).