Quiz for Oxidation number

Q1: What is the oxidation number of oxygen in most compounds?

A. -2 B. +2 C. 0 D. -1

Q2: The oxidation number of an element in its free state is:

A. 0 B. +1 C. -1 D. Depends on the element

Q3: In H2O2, the oxidation number of oxygen is:

A. -1 B. -2 C. 0 D. +1

Q4: The oxidation number of hydrogen in most compounds is:

A. +1 B. -1 C. 0 D. Depends on the compound

Q5: Sum of oxidation numbers in a neutral compound is:

A. 0 B. 1 C. -1 D. Depends on the compound

Q6: In polyatomic ions, sum of oxidation numbers equals:

A. Charge on the ion B. Zero C. One D. Depends on element

Q7: Oxidation is defined as:

A. Increase in oxidation number B. Decrease in oxidation number C. Gain of electrons D. Loss of oxygen

Q8: Reduction is:

A. Decrease in oxidation number B. Increase in oxidation number C. Loss of electrons D. Gain of oxygen

Q9: In NaCl, oxidation number of Na is:

A. +1 B. 0 C. -1 D. +2

Q10: In NaCl, oxidation number of Cl is:

A. -1 B. 0 C. +1 D. -2

Q11: In elemental form, oxidation number is:

A. Zero B. Depends on element C. +1 D. -1

Q12: The oxidation number of sulfur in H2SO4 is:

A. +6 B. +4 C. -2 D. 0

Q13: Oxidizing agent:

A. Gets reduced B. Gets oxidized C. Remains unchanged D. None of these

Q14: Reducing agent:

A. Gets oxidized B. Gets reduced C. Remains unchanged D. None of these

Q15: In MnO4- (permanganate ion), oxidation number of Mn is:

A. +7 B. +4 C. +6 D. +2

Q16: The sum of oxidation numbers in SO4^2- is:

A. -2 B. 0 C. +2 D. +4

Q17: In balancing redox reactions, oxidation numbers:

A. Help identify electrons lost or gained B. Are ignored C. Are always zero D. Are random

Q18: Oxidation number of chlorine in Cl2 is:

A. 0 B. +1 C. -1 D. +2

Q19: In HClO3, oxidation number of Cl is:

A. +5 B. +3 C. +1 D. -1

Q20: Which element has variable oxidation states?

A. Transition metals B. Noble gases C. Alkali metals D. Halogens only