CBSE Class 11 Redox Reactions — practice questions
68 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice CBSE Class 11 Redox Reactions in the app →Per NCERT §7.1 (classical), the term OXIDATION (broadened) covers which of the following changes?Per NCERT §7.2, in modern (electron-transfer) terms, OXIDATION is defined as which process?Per NCERT §7.2, an OXIDISING AGENT is best described as which kind of species?Per NCERT §7.2 eqn 7.14, in the reaction 2Na(s) + S(s) → Na₂S(s), which species is OXIDISED?Per NCERT §7.2.1, in Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s), which acts as the reducing agent?Per NCERT §7.2.1, the electron-releasing (reducing) tendency among the metals Zn, Cu, Ag is in which order?Per NCERT §7.1, oxidation can also be characterised as the addition of which kind of element to a substance?Per NCERT §7.1 eqn 7.4, in 2H₂S(g) + O₂(g) → 2S(s) + 2H₂O(l), H₂S is oxidised mainly because of which change?Per NCERT §7.2, a HALF REACTION is best characterised as which kind of equation?Per NCERT Problem 7.2, in 2Na(s) + H₂(g) → 2NaH(s), the role of hydrogen is which?Per NCERT §7.2.1, when Cu(s) is placed in AgNO₃(aq), the equilibrium of Cu + 2Ag⁺ → Cu²⁺ + 2Ag favours which sPer NCERT §7.2.1, when Co(s) is placed in NiSO₄(aq), which describes the position of the resulting equilibriumPer NCERT §7.3 (rule 3), the oxidation number of oxygen in a normal PEROXIDE (e.g. H₂O₂, Na₂O₂) is which?Per NCERT §7.3 (rule 3), the oxidation number of oxygen in a SUPEROXIDE (e.g. KO₂, RbO₂) is which?Per NCERT §7.3 (rule 3), the oxidation number of oxygen in OF₂ (oxygen difluoride) is which?Per NCERT §7.3 (rule 4), the oxidation number of hydrogen in a binary metal HYDRIDE (e.g. NaH, LiH, CaH₂) is wPer NCERT §7.3 (rule 1), the oxidation number of an atom in any element in its FREE / UNCOMBINED form (e.g. O₂Per NCERT §7.3 rules, the oxidation number of sulphur in H₂SO₄ is which?Per NCERT §7.3 rules, the oxidation number of chromium in K₂Cr₂O₇ is which?Per NCERT §7.3 rules, the oxidation number of Mn in KMnO₄ is which?Per NCERT §7.3 Problem 7.3 (Stock notation), the iron in Fe₂O₃ is best written with which Roman numeral?Per NCERT §7.3 (Stock notation), MnO₂ is best written as which formula?Per NCERT §7.3 (highest oxidation states), the highest oxidation state of chlorine in its compounds (e.g. HClOPer NCERT §7.3 (fractional ox. numbers box), the AVERAGE oxidation number of S in S₄O₆²⁻ (tetrathionate) is whPer NCERT §7.3.1, a COMBINATION reaction is classified as redox under which condition?Per NCERT §7.3.1, the decomposition CaCO₃(s) → CaO(s) + CO₂(g) is classified as which kind of reaction?Per NCERT §7.3.1(3), the reaction CuSO₄(aq) + Zn(s) → ZnSO₄(aq) + Cu(s) is classified as which type?Per NCERT §7.3.1(3a) eqn 7.32, the reaction Cr₂O₃(s) + 2 Al(s) → Al₂O₃(s) + 2 Cr(s) is an example of which indPer NCERT §7.3.1(3b), the OXIDISING strength among halogens decreases in which order?Per NCERT §7.3.1(3b), the reaction Cl₂(g) + 2 KI(aq) → 2 KCl(aq) + I₂(s) is an example of which kind?Per NCERT §7.3.1(4), a DISPROPORTIONATION reaction is best described as which kind?Per NCERT eqn 7.45, in 2H₂O₂(aq) → 2H₂O(l) + O₂(g), the oxidation states of O in H₂O₂, O₂, and H₂O are which sPer NCERT eqn 7.48, Cl₂(g) + 2 OH⁻ → ClO⁻ + Cl⁻ + H₂O has Cl in which oxidation states in products?Per NCERT §7.3.1(4), which halogen does NOT undergo disproportionation with alkali (unlike Cl₂, Br₂, I₂)?Per NCERT Problem 7.5, among the chlorine oxoanions ClO⁻, ClO₂⁻, ClO₃⁻, ClO₄⁻, which one does NOT disproportioPer NCERT §7.3.1(3b) eqn 7.40, the reaction 2 H₂O + 2 F₂ → 4 HF + O₂ shows which species being oxidised?Per NCERT §7.3.2, the TWO methods used to balance redox reactions are which?Per NCERT Problem 7.8, the balanced ionic equation for Cr₂O₇²⁻ + SO₃²⁻ → Cr³⁺ + SO₄²⁻ in acid solution uses hoPer NCERT Problem 7.8, the same Cr₂O₇²⁻ + SO₃²⁻ balanced equation produces how many H₂O molecules on the produPer NCERT §7.3.2 (half-reaction method), Step 4 for an ACIDIC medium adds which species?Per NCERT eqn 7.54, the balanced reduction half-reaction for Cr₂O₇²⁻ in acidic medium consumes how many H⁺?Per NCERT eqn 7.54, the balanced reduction half-reaction for Cr₂O₇²⁻ in acidic medium gains how many electronsPer NCERT §7.3.2 (half-reaction method) for a BASIC medium, oxygen balance is achieved by adding which speciesPer NCERT Problem 7.9, the balanced reaction of MnO₄⁻ with Br⁻ in BASIC medium gives MnO₂ and which Br speciesPer NCERT §7.3 (definitions revised), OXIDATION in terms of oxidation number means which change?Per NCERT Problem 7.4, in 2Cu₂O(s) + Cu₂S(s) → 6Cu(s) + SO₂(g), which species is REDUCED?Per NCERT Problem 7.6, the reaction N₂(g) + O₂(g) → 2 NO(g) is classified as which type of redox?Per NCERT Problem 7.6, the reaction 2 NO₂(g) + 2 OH⁻ → NO₂⁻ + NO₃⁻ + H₂O is classified as which type?In terms of electron transfer, which statement correctly defines oxidation and reduction?Consider the reaction $2\mathrm{Na}(s) + \mathrm{Cl}_2(g) \rightarrow 2\mathrm{NaCl}(s)$. Identify the oxidisiIn the reaction $\mathrm{H}_2\mathrm{S}(g) + \mathrm{Cl}_2(g) \rightarrow 2\mathrm{HCl}(g) + \mathrm{S}(s)$, wIn the thermite reaction $3\mathrm{Fe}_3\mathrm{O}_4(s) + 8\mathrm{Al}(s) \rightarrow 9\mathrm{Fe}(s) + 4\mathWhat is the oxidation number of sulphur in $\mathrm{H}_2\mathrm{SO}_4$? Apply the standard rules: H is $+1$, OWhich one of the following reactions is a DISPROPORTIONATION reaction — i.e., a reaction in which the same eleIn the older, classical view of redox reactions (before electron-transfer was understood), OXIDATION was definIn the modern electron-transfer view, a REDUCING AGENT isWhich of the following best classifies as a COMBINATION redox reaction (i.e. two or more substances combine toWhich of the following is a DECOMPOSITION redox reaction?The reaction $\mathrm{Zn}(s) + \mathrm{CuSO}_4(aq) \rightarrow \mathrm{ZnSO}_4(aq) + \mathrm{Cu}(s)$ is best cWhat is the oxidation number of manganese in potassium permanganate, $\mathrm{KMnO}_4$? (K is $+1$, O is $-2$ What is the oxidation number of chromium in potassium dichromate, $\mathrm{K}_2\mathrm{Cr}_2\mathrm{O}_7$?In the thiosulphate ion $\mathrm{S}_2\mathrm{O}_3^{2-}$, what is the AVERAGE oxidation number of sulphur?How many electrons are transferred per dichromate ion when $\mathrm{Cr}_2\mathrm{O}_7^{2-}$ is reduced to $\maBalance the half-reaction $\mathrm{MnO}_4^- \rightarrow \mathrm{Mn}^{2+}$ in acidic medium. How many electronsDetermine the oxidation number of oxygen in oxygen difluoride, $\mathrm{OF}_2$. (Note: F is the most electroneConsider the laboratory preparation of chlorine: $2\mathrm{KMnO}_4 + 16\,\mathrm{HCl} \rightarrow 2\,\mathrm{KWhat is the AVERAGE oxidation number of sulphur in the tetrathionate ion $\mathrm{S}_4\mathrm{O}_6^{2-}$?In the reaction $\mathrm{H_2O_2}(aq) + \mathrm{Cl}_2(g) \rightarrow 2\,\mathrm{HCl}(aq) + \mathrm{O}_2(g)$, wh