Given below are two statements: Statement I: Mohr's salt is composed of only three types of ions-ferrous, ammonium and sulphate. Statement II: If the molar conductance at infinite dilution of ferrous, ammonium and sulphate ions are mathbfx_1, mathbfx_2 and mathbfx_3 mathrmS\ cm^2\ mathrmmol^-1, respectively then the molar conductance for Mohr's salt solution at infinite dilution would be given by mathbfx_1 + mathbfx_2 + 2mathbfx_3. In the light of the given statements, choose the correct answer from the options given below:

Solution & Explanation

### Related Formula lambda_m^infty = nu_+ lambda_+^infty + nu_- lambda_-^infty ### Core Logic Statement I: Mohr's salt is a double salt with chemical formula: mathrmFeSO_4 cdot (NH_4)_2SO_4 cdot 6H_2O When dissolved in water, it completely dissociates into three distinct ionic species: mathrmFe^2+ text (ferrous), quad mathrmNH_4^+ text (ammonium), quad textand mathrmSO_4^2- text (sulphate) Thus, Statement I is true. Statement II: According to Kohlrausch's law of independent migration of ions: lambda_m^infty(textMohr's Salt) = 1 cdot lambda_m^infty(mathrmFe^2+) + 2 cdot lambda_m^infty(mathrmNH_4^+) + 2 cdot lambda_m^infty(mathrmSO_4^2-) lambda_m^infty = x_1 + 2x_2 + 2x_3 Statement II claims the expression is x_1 + x_2 + 2x_3 (missing the coefficient 2 for ammonium). Thus, Statement II is false. ### Pattern Recognition Kohlrausch's law matches stoichiometric coefficients directly to the ion quantities released. Mohr's salt formula contains (NH_4)_2, requiring a multiplier of 2 for ammonium ion conductance. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Electrochemistry Class 12 Chemistry: d- and f-Block Elements

Reference Study Guides

More Electrochemistry Previous-Year Questions — Page 6

Q65 jee_main_2024_31_jan_morning Batteries
The metals that are employed in the battery industries are A. Fe B. Mn C. Ni D. Cr E. Cd Choose the correct answer from the options given below:
  • A. textB, C and E only
  • B. textA, B, C, D and E
  • C. textA, B, C and D only
  • D. textB, D and E only

Solution

### Core Logic Mn, Ni, and Cd metals are predominantly used in battery industries. - Mn is used in dry cells (Leclanche cell). - Ni and Cd are used in Nickel-Cadmium (Ni-Cd) rechargeable batteries. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Electrochemistry
Q67 jee_main_2024_31_jan_morning Electrolytic Conductance
Identify the factor from the following that does not affect electrolytic conductance of a solution.
  • A. textThe nature of the electrolyte added.
  • B. textThe nature of the electrode used.
  • C. textConcentration of the electrolyte.
  • D. textThe nature of solvent used.

Solution

### Core Logic Conductivity of an electrolytic cell is affected by the concentration of the electrolyte, the nature of the electrolyte, and the nature of the solvent. It does not depend on the nature of the electrode used. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Electrochemistry
Q90 jee_main_2024_31_jan_morning Faraday's Laws of Electrolysis
One Faraday of electricity liberates x times 10^-1 gram atom of copper from copper sulphate, x is
Numerical Answer. Answer: 5 to 5

Solution

### Core Logic The reduction reaction for copper is: Cu^2+ + 2e^- rightarrow Cu This shows that 2 moles of electrons (2 Faraday) are required to deposit 1 mole (or 1 gram atom) of Cu. Therefore, 1 Faraday of electricity will deposit: frac12 = 0.5 text moles of Cu ### Step 1: Finding x 0.5 text mole = 0.5 text gram atom = 5 times 10^-1 text gram atom Hence, x = 5. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Electrochemistry

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