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UPCET / UPSEE Electrochemistry — practice questions

Explore 115 free Electrochemistry questions in UPCET / UPSEE Chemistry. Open each question or exercise to read its content, reference answers and available explanation.

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Electrochemistry questions and exercises with answers

Showing questions 1–30 of 115.

For a galvanic cell, the standard cell EMF is given by:Read the answer and worked solution →The Nernst equation for a half-cell reaction at 298 K is:Read the answer and worked solution →A substance whose aqueous solution conducts electricity by dissociation into ions is called a(n):Read the answer and worked solution →The SI unit of electrical conductance is:Read the answer and worked solution →**Conductivity** $\kappa$ of a solution refers to:Read the answer and worked solution →**Molar conductivity** $\Lambda$ is defined as:Read the answer and worked solution →On dilution, the **conductivity** ($\kappa$) of an electrolyte solution:Read the answer and worked solution →On dilution, the **molar conductivity** ($\Lambda$) of an electrolyte:Read the answer and worked solution →The **degree of dissociation** $\alpha$ of a weak electrolyte is related to its molar conductivity by:Read the answer and worked solution →**Cell constant** of a conductivity cell is given by:Read the answer and worked solution →For a **strong** electrolyte (e.g. KCl), the variation of molar conductivity $\Lambda$ with $\sqrt{c}$ is:Read the answer and worked solution →The molar conductivity of 0.05 M BaCl₂ solution at 25 °C is 223 Ω⁻¹ cm² mol⁻¹. Its conductivity ($\kappa$) is:Read the answer and worked solution →A conductivity cell containing 0.01 M KCl ($\kappa = 0.00141$ Ω⁻¹ cm⁻¹) at 25 °C has resistance 604 Ω. The cell constant is:Read the answer and worked solution →The Gibbs free-energy change of a galvanic cell reaction is given by:Read the answer and worked solution →A salt bridge in a galvanic cell:Read the answer and worked solution →For the cell Zn|Zn²⁺‖Cu²⁺|Cu with $E^0_{cell} = 1.10$ V, the equilibrium constant $K$ at 298 K ($n=2$, RT/F = 0.0257) is approximately:Read the answer and worked solution →In a galvanic cell, the oxidation half-reaction takes place at the:Read the answer and worked solution →In the standard Daniell cell (Zn|Zn²⁺ || Cu²⁺|Cu) at unit concentrations, the cell EMF is:Read the answer and worked solution →The standard hydrogen electrode (SHE) is assigned a standard electrode potential of:Read the answer and worked solution →The Nernst equation for the cell reaction aA + bB → cC + dD at 298 K is:Read the answer and worked solution →For the cell Zn | Zn²⁺ || Cu²⁺ | Cu at 298 K, the Nernst equation expresses E_cell as:Read the answer and worked solution →For the cell Cu(s) + 2Ag⁺ → Cu²⁺ + 2Ag, E°_cell = +0.46 V at 298 K. The equilibrium constant K_c is approximately:Read the answer and worked solution →The relation between cell EMF and Gibbs free-energy change is:Read the answer and worked solution →The SI unit of conductance (G = 1/R) is:Read the answer and worked solution →The relation between conductivity κ, cell constant (l/A), and conductance G is:Read the answer and worked solution →The molar conductivity Λ_m of an electrolyte solution is defined as:Read the answer and worked solution →As an electrolyte solution is diluted, the **conductivity (κ)** and **molar conductivity (Λ_m)** respectively:Read the answer and worked solution →Given λ°(Ca²⁺) = 119.0 and λ°(Cl⁻) = 76.3 S cm² mol⁻¹, the limiting molar conductivity of CaCl₂ is:Read the answer and worked solution →Given Λ°_m for HCl, NaAc, NaCl = 425.9, 91.0, 126.4 S cm² mol⁻¹ respectively. Calculate Λ°_m for acetic acid (HAc):Read the answer and worked solution →For a weak electrolyte at concentration c, the degree of dissociation α can be approximated as:Read the answer and worked solution →

Worked practice questions

For a galvanic cell, the standard cell EMF is given by:

  1. $E^{\circ}_{\text{cell}} = E^{\circ}_{\text{cathode}} + E^{\circ}_{\text{anode}}$
  2. $E^{\circ}_{\text{cell}} = E^{\circ}_{\text{anode}} - E^{\circ}_{\text{cathode}}$
  3. $E^{\circ}_{\text{cell}} = E^{\circ}_{\text{cathode}} - E^{\circ}_{\text{anode}}$
  4. $E^{\circ}_{\text{cell}} = -2 E^{\circ}_{\text{anode}}$
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Correct answer: C. $E^{\circ}_{\text{cell}} = E^{\circ}_{\text{cathode}} - E^{\circ}_{\text{anode}}$

$E^{\circ}_{\text{cell}} = E^{\circ}_{\text{cathode}} - E^{\circ}_{\text{anode}}$, where both potentials are listed as standard *reduction* potentials. For a spontaneous galvanic cell, $E^{\circ}_{\text{cell}} > 0$, which means the cathode has the higher reduction potential. This is just an algebraic restatement of "reduction happens at the cathode".

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The Nernst equation for a half-cell reaction at 298 K is:

  1. $E = E^{\circ} - n \cdot 0.059 \log Q$
  2. $E = E^{\circ} + \dfrac{0.059}{n} \log Q$
  3. $E = E^{\circ} - \dfrac{0.059}{n} \log Q$
  4. $E = E^{\circ} - 0.059 \log [\mathrm{H^+}]$
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Correct answer: C. $E = E^{\circ} - \dfrac{0.059}{n} \log Q$

Full form: $E = E^{\circ} - \dfrac{RT}{nF} \ln Q$. At 298 K with $\log_{10}$, the constants collapse to $\dfrac{0.0592}{n}$, often rounded to $\dfrac{0.059}{n}$. Here $n$ is the number of electrons exchanged in the half-cell, and $Q$ is the reaction quotient. The negative sign matters: when $Q > 1$ (products dominate), $E$ is below $E^{\circ}$. Option B has the wrong sign; option D scrambles where $n$ goes.

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A substance whose aqueous solution conducts electricity by dissociation into ions is called a(n):

  1. Electrolyte
  2. Semiconductor
  3. Non-electrolyte
  4. Insulator
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Correct answer: A. Electrolyte

Electrolytes (salts, strong/weak acids, bases) dissociate into ions in solution and conduct electricity. Sucrose and urea do not dissociate and are non-electrolytes.

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More Chemistry topics

Ideal and Non-Ideal SolutionsIdeal SolutionsNon-Ideal SolutionsReactions in Aqueous SolutionElectrochemical SeriesCoordination CompoundsSolutionsSurface Chemistry