Category 8: Factors Affecting Enzyme Activity (Questions 71-80)

📚 Chemistry Common questions about  Redox Reactions & Oxidation States:

1.  Which of the following is a defining characteristic of ALL redox reactions?
    a)  Formation of a precipitate
    b)  Transfer of protons (H⁺ ions)
    c)  Transfer of electrons
    d)  Release of heat (exothermic reaction)
   

Answer: c) Transfer of electrons

2.  In the following reaction, which species is being oxidized?  2 Ag⁺(aq) + Cu(s)  →  2 Ag(s) + Cu²⁺(aq)   
     a)  Ag⁺
     b)  Cu
     c)  Ag
     d)  Cu²⁺
   

Answer: b)  Cu  (Loses electrons, oxidation number increases)

3.  What is the oxidation state of sulfur (S) in H₂SO₄?
    a)  +2
    b)  +4
    c)  +6
    d)  -2
   

Answer: c)  +6 

4.  Which of the following is NOT a possible oxidation state of chlorine (Cl)?
    a)  -1
    b)  +1
    c)  +3
    d)  +6
   

Answer: d)  +6 (Chlorine can have oxidation states from -1 to +7, but not +6)

5.  In a balanced half-reaction, what is used to balance the charges?
    a)  H₂O
    b)  H⁺ ions
    c)  Electrons (e⁻)
    d)  All of the above
   

Answer: c) Electrons (e⁻)

6.  A reducing agent is a species that:
    a)  Loses electrons and is reduced.
    b)  Gains electrons and is reduced.
    c)  Loses electrons and is oxidized.
    d)  Gains electrons and is oxidized.
   

Answer: c) Loses electrons and is oxidized.

7.  In the compound Na₂O₂, what is the oxidation state of oxygen (O)?
    a)  -2
    b)  -1
    c)  0
    d)  +1
   

Answer: b)  -1  (This is a peroxide)

8.  Disproportionation is a type of redox reaction in which:
    a)  The same element is both oxidized and reduced.
    b)  Two different elements are oxidized.
    c)  No electrons are transferred.
    d)  The reaction is always endothermic.
  

Answer: a)  The same element is both oxidized and reduced.

9.  What is the oxidation state of manganese (Mn) in the permanganate ion (MnO₄⁻)?
    a)  +2
    b)  +4
    c)  +7
    d)  -1


    Answer: c)  +7 

10. Which of the following statements is TRUE about oxidation states?
     a) They always represent the actual charges on atoms in a compound.
     b) They are used to keep track of electron transfer in chemical reactions.
     c) They are always positive whole numbers.
     d) They are not applicable to covalent compounds.

     Answer: b) They are used to keep track of electron transfer in chemical reactions.


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Category 9: Enzyme Regulation and Inhibition (Questions 81-90)