Chemistry · Physics

Electrochemistry and Current Electricity

224 Questions

Review fundamental concepts of electrochemistry and current electricity through these practice questions. The set includes numerical problems on electrolysis, drift velocity, and electrode potentials. These topics frequently appear in engineering, CSIR NET, and state PSC prelims examinations for thorough preparation.

Electrolysis calculationsElectrode potentialNernst equationDrift velocityFuel cellsMolar conductivity

Electrochemistry and Current Electricity Questions

Multiple choice physics dynamics - explaining motion exponentiation index notation and products of prime factors powers

1 MeV is equal to

  1. $1.6\times 10^{13} Joules$
  2. $1.6\times 10^{13} cal.$
  3. $1.6\times 10^{13} ergs$

  4. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

An electronvolt is a unit of energy equal to the work done on an electron accelerated through a potential difference of $1$ volt.


$1 eV=1.6\times10^{-19}\ J$ 

$\therefore1\,MeV=1.6\times 10^{-19}\times10^{6}\,Joules$

$1\ MeV=1.6\times10^{-13}\ J$

Multiple choice physics magnetism and matter magnetic materials behaviour of substances in magnetic field classification of magnetic materials

The relative permeability of silicon is $0.99837$ and that of palladium is $1.00692$, choose the correct option from the following :

  1. silicon is paramagnetic and palladium is ferromagnetic

  2. silicon is ferromagnetic and palladium is paramagnetic

  3. silicon is diamagnetic and palladium is paramagnetic

  4. Both are paramagnetic
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Diamagnetic           Paramagnetic             Ferromagnetic
-1 $\leq$ $\chi$ < 0                  0 < $\chi$ < $\varepsilon$                  $\chi$ >> 1
0 $\leq$ $\mu _{r}$ < 1                1 < $\mu _{r}$ < 1+ $\varepsilon$               $\mu _{r}$ >> 1
$\chi$ $=$ magnetic susceptibility
$\mu _{r}$ $=$ relative permeability.
$\varepsilon$ < 1 and small.

Multiple choice chemistry electrolysis electrolytes and non-electrolytes introduction to electrolysis chemical reactions

In which of the following electrolysis, the composition of electrolyte is expected to remain constant under optimum conditions:

  1. Aq. AgNO$ _{3}$ solution between Ag electrodes
  2. Aq. CuSO$ _{4}$ solution between Pt electrodes

  3. Fused NaCl between Pt electrodes
  4. Aqueous AgNO$ _{3}$ solution between Pt electrodes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In case of Aq.  $AgNO _3$  with Ag electrodes, metal from anode goes to the solution and metal from solution goes to the cathode, hence the composition of electrolyte does not change with time and remain constant.

Hence. option A is correct.

Multiple choice chemistry electrolysis electrolytes and non-electrolytes introduction to electrolysis chemical reactions

Which of the following will form the cathode with respect to iron anond in an electrolytic cell ?

  1. Mg

  2. Al

  3. Cu

  4. Zn
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In an electrochemical cell, the metal with a higher reduction potential (more noble) acts as the cathode, while the metal with a lower reduction potential (more active) acts as the anode. Copper (Cu) has a higher reduction potential than iron (Fe).

Multiple choice physics electrical conductivity of liquids does liquid conduct electricity? liquids conduct electricity do liquids conduct electricity?

Which solution will conduct the current?

  1. Sugar in water

  2. Sugar in ethanol

  3. Iodine in ethanol
  4. $MgCl _2$ in water
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In water magnesium chloride ionizes to form ions and these ions conduct electricity. Sugar and iodine are non electrolytes. They do not dissociate into ions in aqueous solution. Hence, they do not conduct electricity.

Multiple choice chemistry ionic equilibrium introduction to ionic equilibria in solution ionic equilibrium in solution ionisation of weak acids and weak bases

Two electrolytic cells containing molten solutions of Nickel chloride and Aluminium chloride are connected in series. If same amount of electric current is passed through them, what will be the weight of Nickel obtained when $18gm$ of Aluminium is obtained? $\left( Al-27gm/mole,Ni-58.5gm/{ mole }^{ -1 } \right) $

  1. $58.5gm$
  2. $117gm$
  3. $29.25gm$
  4. $5.85gm$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
$By Faraday's Second Law$
$\frac{(m)N _{i}}{(m) _{N _{A1}}}=\frac{(E)N _{i}}{(E) _{N _{A1}}}$
$\frac{(m)N _{i}}{18}=\frac{58.5\times 2}{3\times 27}$
$(m){N _{i}}=58.5 g$

Multiple choice types of cells electricity physics

For a cell reaction involing a two-electron change, the standard e.m.f of the cell is fonud to be$0.295V$ at $25^{o}C$. The equilibrium constant of the reaction at $25^{o}C$ will be:

  1. $10$
  2. $1\ \times 10^{10}$
  3. $1\ \times 10^{-10}$
  4. $29.5\ \times 10^{-2}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Multiple choice types of cells electricity physics

A $100$ watt, $110$ volt lamp is connected in series with an electrolytic cell containing $CaSO _4$ solution, the weight of Cd deposited by the current for $10$ hrs is (Sl.wt. of Cd=112.4)

  1. $19.06$g
  2. $38.12$g
  3. $1.906$g
  4. $3.812$g
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice types of cells electricity physics

What is the e.m.f. of a dry cell ?

  1. $1.5 V$
  2. $2.5 V$
  3. $1.1 V$
  4. $-1.1 V$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A common dry cell is the zinc–carbon battery, sometimes called the dry Leclanché cell, with a nominal voltage of 1.5 volts, the same as the alkaline battery (since both use the same zinc–manganese dioxide combination).Hence the correct option A.
Multiple choice types of cells electricity physics

Electro chemical equivalent of substance is 0.0006735 ; its eq. wt. is :

  1. 65

  2. 67.35

  3. 130

  4. cannot be calculated
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The electrochemical equivalent (Z) is related to equivalent weight (E) by the formula Z = E / F, where F is Faraday's constant (approximately 96500 C/mol). E = Z * F = 0.0006735 * 96500 = 64.99, which rounds to 65.

Multiple choice types of cells electricity physics

The common dry cell produces a voltage of

  1. $1.5 V$
  2. $4 V$
  3. $2 V$
  4. $3 V$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A common dry cell is zinc-carbon cell with a normal voltage of 1.5 V , same as the alkaline cell.

Multiple choice types of cells electricity physics

A cell constructed by coupling a standard copper electrode and a standard magnesium electrode has emf of $2.7$ volts. If the standard reduction potential of copper electrode of $+0.34\ V$, that of magnesium electrode is

  1. $+3.04\ V$
  2. $-3.04\ V$
  3. $+2.36\ V$
  4. $-2.36\ V$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The cell EMF is E_cell = E_cathode - E_anode. Given E_cell = 2.7 V and E_copper = +0.34 V (cathode), then 2.7 = 0.34 - E_magnesium. Solving for E_magnesium gives 0.34 - 2.7 = -2.36 V.

Multiple choice chemistry p- block elements-i study of aluminium chloride study of aluminium structure of some compounds

${Al} _{2}{O} _{3}$ is reduced by electrolysis at low potential and high currents. If $4.0\times {10}^{4}$ amperes of current is passed through molten ${Al} _{2}{O} _{3}$ for 6 hours, what mass of aluminium is produced? (Assume 100% current efficiency, At. mass of $Al=27g{mol}^{-1}$)

  1. $1.3\times {10}^{4}g$
  2. $9.0\times {10}^{3}g$
  3. $8.1\times {10}^{4}g$
  4. $2.4\times {10}^{5}g$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$Al _2O _3(l) \rightarrow2Al^{3+}(l) + 3O^{2-}(l) $

Reduction equation of $Al^{3+}: $
$Al^{3+}(aq) + 3e^- \rightarrow Al(s) $

As,

Ampere = Coulomb / sec 

Time unit should be second. 
$6 hr \times 60 \dfrac{min}{ hr} \times 60 \dfrac{sec}{ min} = 21600 sec $
Coulomb = Ampere x second $= 40000 \times 21600 = 8.64\times10^8 $

1 mol $e^-$ carries a charge of 1 faraday, or 96485 coulombs. 
Then the mole of $e^-$ used in the electrolysis will be: 

$\dfrac{8.64\times10^8   \text{coulombs}}{ 96485 -\text{coulombs/mol}}- of -e^- = 8954.8  \text{mol of} -e^- $

According to the reduction equation, 3 moles of e- are needed to reduce 1 mol of Al^3+ to Al metal. 
Then , the mole of Al to be deposited at the cathode will be; 
$\dfrac{8954.8 \text{mol e-} }{ \dfrac{3 -\text{mol of e-}}{\text{mol Al}}} = 2985\text{ mol Al} $

Molar mass of $Al : 26.98 g/mol $
Mass of Al produced$: 2985 mol \times 26.98 g/mol = 80535 g $
$Al = 8.1\times10^4 g$

Multiple choice botany plant water relation diffusion pressure deficit other pressure components osmosis in plants

Which of the following equation is correct for incipient plasmolysed cell ?

  1. $DPD=OP-TP$
  2. $OP=TP$
  3. ${ \Psi } _{ w }={ \Psi } _{ s }+{ \Psi } _{ p }$
  4. ${ \Psi } _{ w }={ \Psi } _{ s }-{ \Psi } _{ p }$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Diffusion pressure deficit - It is described as the ability of water to move is used to measure in terms of diffusion pressure. 


(C) $\Psi _w = \Psi _s + \Psi _p$

The point during which the protoplast is just pulled or moved away from the cell wall is called incipient plasmolysis.