Redox Reaction

Is calcium oxidized or reduced in the following reaction? 
2CaO--> 2Ca + O₂

• Oxidized
• Reduced

If in a reaction, copper is reduced; its number of electrons has:

• Increased
• Decreased
• Remained Constant
• Varies Randomly

What is oxidation number of Cr in Cr₂O_7^2-?

• -2
• +2
• +6
• +12

What is oxidation number of H in CaH₂?

• +1
• -1
• 0
• +2

An increase in oxidation number.

• more acidic

• reduction

• less basic

• oxidation

What is a half-reaction of this equation, Na + Cl --> NaCl ?

• Cl + e^- --> Cl^-

• Cl - e^- --> Cl^-

• Na --> Na + e^-

• Na° + Cl°--> Na⁺¹Cl^-1

The sum of the oxidation numbers in SCN^- is equivalent to

• 0

• -1

• +1

• +3

Which of the following half reactions correctly represents a reduction half reaction?

• Fe →Fe²⁺ + 2e^-
• Pb⁴⁺ + 2e^- →Pb²⁺
• 2O^-2 →O₂ + 4e^-
• Fe + 3e^- →Fe³⁺

What  will be the result of the following: 
Br₂ + NaF ->

• bromine will replace Na
• Na will replace Br
• Br will replace F
• no reaction will occur

a compound having +2 oxidation state of O is

• H2O

• H2O2

• OF2

• O2F2