- Free elements are assigned an oxidation number of 0.
Which one of the following statements is incorrect?- The oxidation number of calcium in the calcium ion (Ca2+) is 0.
- The oxidation number of hydrogen in the hydrogen molecule (H2) is 0.
- The oxidation number of sodium (Na) in the metal sodium is 0.
- Ions cannot have an oxidation number of 0.
- The oxidation number of a monatomic ion equals the charge on the ion.
Which one of the following statements is correct?- The oxidation number of aluminium in the Al3+ ion is +3.
- The oxidation of the fluoride ion is 0.
- The oxidation number of the hydroxide ion (OH-) is -1.
- Every atom may have only one oxidation number.
- The Alkali metals of group I are always assigned an oxidation number of +1. Which one of the following statements is incorrect?
- Hydrogen has an oxidation number of -1 in lithium hydride (LiH).
- When sodium is bonded to chlorine in NaCl, it has an oxidation number of +1.
- When there is an increase in the oxidation number of an atom in a chemical reaction, oxidation is said to occur.
- Free potassium has an oxidation number of +1.
- If the halogens have an oxidation number of -1, what is the oxidation number of calcium in calcium chloride (CaCl2)?
- +2
- +1
- 0
- −2
- Oxygen in a compound has an oxidation number of -2. One of the exceptions to this rule is when oxygen
- is bonded to the more electronegative fluorine.
- is bonded to chlorine.
- is bonded to a metal forming a metallic oxide.
- is bonded to hydrogen in water.
- Hydrogen has an oxidation number of +1 except in
- metal hydrides.
- hydroxides.
- acids.
- hydrogencarbonates.
- The sum of the oxidation numbers of all of the atoms in a neutral compound is 0. What is the oxidation number of sulfur in H2SO4?
- +6
- −6
- +1
- −2
- If the sum of the oxidation numbers in a complex ion is equal to the charge on that ion, what is the oxidation number of manganese in MnO4-?
- +7
- +2
- +8
- −7
- The alkaline earth metals (Be, Mg, Ca, Sr, Ba, and Ra) are always assigned an oxidation state of +2.
What is the oxidation number of sulfur in magnesium sulfide (MgS)?- −2
- −1
- −4
- +2
- Which one of the following elements can only have one oxidation number?
- Fluorine
- Hydrogen
- Oxygen
- Chromium
- True or false? All monatomic ions have an oxidation number of +1.
- FALSE
- TRUE
- Which one of the following elements does NOT have a fixed oxidation number?
- Sulfur
- Magnesium
- Fluorine
- Sodium
- What is the oxidation number of carbon in the carbonate ion (CO32−)?
- +4
- +2
- −4
- +6
- What is the oxidation number of nitrogen in N2O4
- +4
- +3
- +5
- −3
- What is the oxidation number of iron in Fe2O3?
- +3
- +2
- +4
- -2
- What is the oxidation number of chlorine in KClO3?
- +5
- +1
- −1
- +3
- What are the oxidation numbers of copper on the left and right hand sides of the following equation?
Cu + 2AgNO3 → 2Ag + Cu(NO3)2- 0 and +2
- 0 and +1
- +2 and +1
- +1 and +2
- Which one of the following species has an oxidation number of 0 in sucrose whose chemical formula is C12H22O11
- Carbon
- Hydrogen
- Oxygen
- None of them
- In which of the following species does nitrogen have an oxidation number of +1?
- N2O
- NO3-
- NO2
- N2O4
- When mercuric oxide is heated it breaks down to mercury and oxygen as follows:
HgO → Hg + O2
What is the oxidation number of mercury in mercuric oxide?- +2
- +1
- −2
- −1
- What are the oxidation numbers of the elements in sulfuric acid, H2SO4?
- H = +1, S = +6, O = −2
- H = +1, S = +4, O = −2
- H = +2, S = +1, O = +4
- H = +2, S = +6, O = −8