General
✓✗When Cl2 gas reacts with hot and concentrated sodium hydroxide solution, the oxidation number of chlorine changes from
- zero to −1 and zero to +5
- zero to +1 and zero to −3
- zero to +1 and zero to −5
- zero to −1 and zero to +3
General
✓✗Statement I: Oxidation number of Cr in CrO5 is +10.
Statement II: CrO5 contains two peroxide linkages.
Statement II: CrO5 contains two peroxide linkages.
- Both Statement I and Statement II are correct
- Both Statement I and Statement II are incorrect
- Statement I is correct but Statement II is incorrect
- Statement I is incorrect but Statement II is correct
General
✓✗For the cell Zn | Zn2+ || Cu2+ | Cu, the half-reaction at the anode is
- Zn → Zn2+ + 2e−
- Cu2+ + 2e− → Cu
- Zn2+ + 2e− → Zn
- Cu → Cu2+ + 2e−
General
✓✗A mixture of potassium chlorate, oxalic acid and sulphuric acid is heated, and the chlorate is reduced to chloride ion while oxalic acid is oxidised to CO2. During the reaction, which element undergoes the maximum change in oxidation number?
- Cl
- S
- C
- H
General
✓✗Tribromooctaoxide, Br3O8, is a neutral molecule. Its correct structure is
General
✓✗When the equation Cu + HNO3 (dilute) → Cu(NO3)2 + NO + H2O is balanced, the coefficients of Cu and HNO3 are
- 3 and 4
- 1 and 4
- 3 and 8
- 1 and 8
General
✓✗In a titration, 20 mL of 0.02 M KMnO4 exactly oxidises 25 mL of an Fe2+ solution in acid. The molarity of Fe2+ is
- 0.004 M
- 0.4 M
- 0.08 M
- 0.016 M
General
✓✗Consider the reactions:
(I) H2O2 + O3 → H2O + 2O2
(II) H2O2 + Ag2O → 2Ag + H2O + O2
The role of hydrogen peroxide in these reactions is respectively
(I) H2O2 + O3 → H2O + 2O2
(II) H2O2 + Ag2O → 2Ag + H2O + O2
The role of hydrogen peroxide in these reactions is respectively
- reducing in (I) and (II)
- oxidising in (I) and (II)
- reducing in (I) and oxidising in (II)
- oxidising in (I) and reducing in (II)
General
✓✗Which of the following is an example of a compound in which the same element shows two different oxidation states?
- NaNO3
- HNO2
- N2O5
- NH4NO2
General
✓✗The oxidation number of oxygen in most of its compounds is
- −2
- +2
- 0
- −1
General
✓✗The reaction C + O2 → CO2 is an example of
- a disproportionation reaction
- a displacement reaction
- a combination redox reaction
- a decomposition reaction
General
✓✗The standard reduction potentials of X, Y and Z are +0.80 V, −0.40 V and +0.34 V. Which statement is correct?
- X can displace Z from its salt solution
- Z is the strongest reducing agent
- X can displace Y from its salt solution
- Y can displace both X and Z from solutions of their salts
General
✓✗Hot concentrated sulphuric acid is a moderately strong oxidising agent. Which of the following reactions does not show its oxidising behaviour?
- C + 2H2SO4 → CO2 + 2SO2 + 2H2O
- S + 2H2SO4 → 3SO2 + 2H2O
- Cu + 2H2SO4 → CuSO4 + SO2 + 2H2O
- CaF2 + H2SO4 → CaSO4 + 2HF
General
✓✗The balanced reduction half-reaction of MnO4− in acidic medium is
- MnO4− + 4H+ + 5e− → Mn2+ + 2H2O
- MnO4− + e− → MnO42−
- MnO4− + 8H+ + 5e− → Mn2+ + 4H2O
- MnO4− + 8H+ + 3e− → Mn2+ + 4H2O
General
✓✗Sulphur dioxide can act as
- neither
- only a reducing agent
- only an oxidising agent
- both an oxidising and a reducing agent