Oxidation Number and Rules for Assigning Oxidation Numbers

Chemistry ⇒ Redox Reactions and Electrochemistry

Oxidation Number and Rules for Assigning Oxidation Numbers starts at 10 and continues till grade 12. QuestionsToday has an evolving set of questions to continuously challenge students so that their knowledge grows in Oxidation Number and Rules for Assigning Oxidation Numbers. How you perform is determined by your score and the time you take. When you play a quiz, your answers are evaluated in concept instead of actual words and definitions used.

See sample questions for grade 10

A compound contains 2 atoms of element X and 3 atoms of oxygen, and the compound is neutral. If the oxidation number of oxygen is -2, what is the oxidation number of X in X₂O₃?

Calculate the oxidation number of chromium in K₂Cr₂O₇.

Calculate the oxidation number of each oxygen atom in O₂F₂.

Calculate the oxidation number of nitrogen in NO₃^-.

Calculate the oxidation number of phosphorus in PO₄^3-.

Determine the oxidation number of chlorine in Cl₂O₇.

A compound contains 2 atoms of element X and 3 atoms of oxygen, and the compound is neutral. If the oxidation number of oxygen is -2, what is the oxidation number of X in X₂O₃?

In the dichromate ion (Cr₂O₇^2-), if the oxidation number of oxygen is -2, what is the sum of the oxidation numbers of the two chromium atoms?

Which of the following elements always has an oxidation number of zero in its elemental form? (1) Oxygen (2) Chlorine (3) Sodium (4) All of the above

Which of the following is NOT a rule for assigning oxidation numbers? (1) The oxidation number of a free element is zero (2) The sum of oxidation numbers in a neutral compound is zero (3) The oxidation number of hydrogen is always -1 (4) The oxidation number of fluorine is always -1

Which of the following is the correct oxidation number for carbon in CH₄? (1) +4 (2) -4 (3) 0 (4) +2

Which of the following is the correct oxidation number for chlorine in ClO₃^-? (1) +3 (2) +5 (3) -1 (4) +7

Fill in the blank: In peroxides, the oxidation number of oxygen is _______.

Fill in the blank: The oxidation number of aluminum in Al₂O₃ is _______.

Fill in the blank: The oxidation number of chlorine in NaClO₃ is _______.

Fill in the blank: The oxidation number of fluorine in all its compounds is _______.

True or False: In compounds, alkali metals (Group 1) always have an oxidation number of +1.

True or False: The oxidation number of all atoms in a molecule of O₃ (ozone) is zero.

True or False: The oxidation number of an atom in a monoatomic ion is equal to the charge of the ion.

True or False: The oxidation number of an element in its diatomic form (e.g., O₂, N₂) is zero.