NEET UG Electrochemical Series — practice questions
120 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice NEET UG Electrochemical Series in the app →In a galvanic cell, the oxidation half-reaction takes place at the:In the standard Daniell cell (Zn|Zn²⁺ || Cu²⁺|Cu) at unit concentrations, the cell EMF is:
If an external opposinThe standard hydrogen electrode (SHE) is assigned a standard electrode potential of:In the standard electrode potential series, F₂/F⁻ has E° = +2.87 V and Li⁺/Li has E° = −3.05 V. Which of the fThe Nernst equation for the cell reaction aA + bB → cC + dD at 298 K is:For the cell Zn | Zn²⁺ || Cu²⁺ | Cu at 298 K, the Nernst equation expresses E_cell as:For the cell Cu(s) + 2Ag⁺ → Cu²⁺ + 2Ag, E°_cell = +0.46 V at 298 K. The equilibrium constant K_c is approximatThe relation between cell EMF and Gibbs free-energy change is:ΔG is an extensive property while E_cell is an intensive property. This means:The SI unit of conductance (G = 1/R) is:The relation between conductivity κ, cell constant (l/A), and conductance G is:The molar conductivity Λ_m of an electrolyte solution is defined as:As an electrolyte solution is diluted, the **conductivity (κ)** and **molar conductivity (Λ_m)** respectively:
For *stKohlrausch's law of independent migration of ions states that the limiting molar conductivity of an electrolytGiven λ°(Ca²⁺) = 119.0 and λ°(Cl⁻) = 76.3 S cm² mol⁻¹, the limiting molar conductivity of CaCl₂ is:Given Λ°_m for HCl, NaAc, NaCl = 425.9, 91.0, 126.4 S cm² mol⁻¹ respectively. Calculate Λ°_m for acetic acid (For a weak electrolyte at concentration c, the degree of dissociation α can be approximated as:The molar conductivity of 0.001028 M acetic acid is 48.15 S cm² mol⁻¹, and Λ°_m(HAc) = 390.5 S cm² mol⁻¹. The Faraday's first law of electrolysis states that the mass of substance deposited at an electrode is proportionaThe Faraday constant F = 96500 C mol⁻¹ represents:A CuSO₄ solution is electrolysed with 1.5 A for 10 minutes. The mass of copper (M = 63.5) deposited at the catIn the electrolysis of **molten** NaCl, the products at the cathode and anode respectively are:During electrolysis of **aqueous** NaCl (brine), the products are:
In a Leclanche (dry) cell,The electrolyte in a lead storage battery (lead-acid) is approximately:In the H₂–O₂ fuel cell used in the Apollo space programme, the electrolyte is:Rusting of iron is an electrochemical phenomenon. At the cathodic spot, the reaction is:Rust is chemically:Why does corrosion of iron require both water and oxygen?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 a Daniell cell with Zn (anode) and Cu (cathode), and $E^\circ(Cu^{2+}/Cu) = +0.34$ V, $E^\circ(Zn^{2+}/Zn) The Nernst equation at $25^\circ$C for a cell with $n$ electrons transferred is $E = E^\circ -$:Electrolysis of molten NaCl at the electrode passes $1$ F of charge. The amount of Na deposited at the cathodeIron rusting on the village ploughshare is best described as:In a GALVANIC cell, the ANODE is:The standard electrode potential of the Standard Hydrogen Electrode (SHE) is defined as:The Daniell cell (Zn-Cu) has E°cell = +1.10 V. Calculate ΔG° (F = 96500 C/mol):The Nernst equation at 25°C for a cell reaction is:Kohlrausch's law is most useful for determining the LIMITING molar conductivity (Λ°m) of:Faraday's first law of electrolysis states that the mass deposited is:A typical LEAD STORAGE BATTERY (car battery) used in vehicles consists of 6 cells in series, each producing abThe byproduct of a hydrogen-oxygen fuel cell (used in space + electric cars) is:GALVANISATION protects iron from rusting by coating it with: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 $\mathrm{H_2O_2}(aq) + \mathrm{Cl}_2(g) \rightarrow 2\,\mathrm{HCl}(aq) + \mathrm{O}_2(g)$, whOxidation in modern terms is defined as:The oxidation state of sulphur in SO₄²⁻ is:The oxidation state of manganese in KMnO₄ is:In Cu + 2 AgNO₃ → Cu(NO₃)₂ + 2 Ag, the species oxidised is:A reducing agent is a substance that:Identify the redox reaction:The disproportionation of chlorine in cold dilute NaOH (3 Cl₂ + 6 OH⁻ → 5 Cl⁻ + ClO₃⁻ + 3 H₂O is the hot reactIn an electrochemical (galvanic) cell, oxidation occurs at the: