Redox Chemistry
From the lesson
29 marksIn which species does nitrogen have an oxidation state of +3?
Learners' Alley, Redox Chemistry slides
Which reaction is not a redox reaction?
Learners' Alley, Redox Chemistry slides
A colourless gas turns a filter paper spotted with aqueous potassium iodide yellow-brown. What can be deduced?
Learners' Alley, Redox Chemistry slides
Which reaction is a disproportionation?
Learners' Alley, Redox Chemistry slides
How many moles of MnO4− react with 1.0 × 10−3 mol of Fe2+ in acid?
Learners' Alley, Redox Chemistry slides
Sodium burns in chlorine: 2Na + Cl2 → 2NaCl.
Learners' Alley, Redox Chemistry slides
Learners' Alley, Redox Chemistry slides
Find the oxidation state of
Learners' Alley, Redox Chemistry slides
Which of these are redox reactions? Explain using oxidation states.
Learners' Alley, Redox Chemistry slides
Sulfur dioxide decolourises acidified potassium manganate(VII) and turns acidified potassium dichromate(VI) green.
Learners' Alley, Redox Chemistry slides
Learners' Alley, Redox Chemistry slides
Learners' Alley, Redox Chemistry slides
Learners' Alley, Redox Chemistry slides
Learners' Alley, Redox Chemistry slides
Learners' Alley, Redox Chemistry slides
Learners' Alley, Redox Chemistry slides
Practice
17 marksWhich formula contains nitrogen with an oxidation state of +5?
2023 XMS O Prelim P1 Q28
In which substance does the nitrogen atom have the same oxidation state as the nitrogen atom in HNO2?
2024 Woodlands O Prelim P1 Q19
Which oxidation state of the underlined element is correct?
| substance | oxidation state | |
|---|---|---|
| A | HNO3 | +3 |
| B | CaSO4 | +6 |
| C | FeO | −3 |
| D | NaHCO3 | +3 |
2024 Zhonghua O Prelim P1 Q21
In which substance does the sulfur atom have the same oxidation number as the sulfur atom in SO2?
2024 CHIJ O Prelim P1 Q22
The oxide of titanium, TiO2, is used as a ‘whitener’ in toothpaste. It is obtained from the ore iron(II) titanate, FeTiO3. What is the change in the oxidation number of titanium from FeTiO3 to TiO2?
2022 SJI O Prelim P1 Q24
In which reaction does the oxidation state of iron remain unchanged?
2024 AMKSS O Prelim P1 Q21
Which method of preparation of magnesium sulfate is an example of a redox reaction?
2024 ANDSS O Prelim P1 Q17
Which reaction is not a redox reaction?
2024 SCSS O Prelim P1 Q20
Iron(II) chloride solution reacts with chlorine gas: 2FeCl2(aq) + Cl2(g) → 2FeCl3(aq). Which statements about this reaction are correct?
1 Fe2+ ions are reduced to Fe3+ ions.
2 Chlorine acts as a reducing agent.
3 Fe2+ ions each lose an electron.
4 Cl2 molecules are reduced to Cl− ions.
2024 Zhenghua O Prelim P1-P3 Q24
The reaction between copper and concentrated nitric acid is shown: Cu + 4HNO3 → Cu(NO3)2 + 2H2O + 2NO2. Which statement about this reaction is correct?
2025 MSHS O Prelim P1 Q15
Acidified potassium manganate(VII) can be used to detect ethanol vapour in the breath of a person who has drunk alcohol. The acidified potassium manganate(VII) turned from purple to colourless in the presence of ethanol vapour. Which explanation is correct?
2024 PLMGSS O Prelim P1 Q26
The equation for the reaction between sodium sulfite and potassium manganate(VII) is shown: 2MnO4− + 6H+ + 5SO32− → 2Mn2+ + 3H2O + 5SO42−. Which ion is reduced and what is the reducing agent?
| ion that is reduced | reducing agent | |
|---|---|---|
| A | MnO4− | H+ |
| B | MnO4− | SO32− |
| C | SO32− | H+ |
| D | SO32− | MnO4− |
2025 JYSS O Prelim P1 Q23
Colour changes are often seen when redox reactions occur. Which colour change is due to the reduction of the underlined reagent?
2024 NASS O Prelim P1-P2 Q25
When chlorine gas dissolves in water a reaction occurs: Cl2 + H2O → HCl + HClO. Which row shows the oxidation number of chlorine in the chlorine-containing species?
| Cl2 | HCl | HClO | |
|---|---|---|---|
| A | −1 | −1 | −1 |
| B | 0 | −1 | −1 |
| C | −1 | +1 | +1 |
| D | 0 | −1 | +1 |
2024 USS O Prelim P2 Q28
Disproportionation is a reaction in which the same element is both oxidised and reduced. Which reaction is an example of disproportionation?
2024 Bukit View O Prelim P1 Q24
Substance X, which is not brown, was bubbled into a solution containing sodium iodide and sodium chloride. The solution turned brown. Which statements can be deduced about substance X?
1 Substance X is an oxidising agent.
2 Substance X must be bromine gas.
3 The iodide in the solution was reduced to aqueous iodine.
2023 XMS O Prelim P1 Q25
Some statements about acids are given below.
I pH is a measure of the H+ concentration in a solution.
II The strength of an acid depends on its concentration.
III Universal Indicator turns orange when placed in a solution of any acid.
IV When acids react with metals, hydrogen ions gain electrons.
Which statements about acids are correct?
2024 SMSS O Sec3 P1 Q11
