Chemistry · Physics

Electrochemistry and Current Electricity

272 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 static electricity properties of charges charge properties of charge

$\displaystyle \frac {4}{25}$ Coulomb of charge contains .................. electrons: 

  1. $10^{15}$
  2. $10^{18}$
  3. $10^{20}$

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

Answer is C.

The formula for quantisation of charge is given as q=ne.
where, q is the amount of charge in Coulumbs, n is the number of charges and e is the charge on the electron.
In this case, q=4/25 C
So, e = $1.6\times { 10 }^{ -19 }C$.
n can be calculated as n=q/e = $\frac { 4 }{ 25 } \times [\frac { 1 }{ 1.6\times { 10 }^{ -19 }C } ]\quad =\quad { 10 }^{ 18 }$ which is the number of electrons.
Hence, 4/25 Coulomb of charge contains ${ 10 }^{ 18 }$ electrons:.

Multiple choice physics static electricity properties of charges charge properties of charge

Fill in the blank.

$1$ Coulomb of charge contains_______number of electrons.

  1. $6.25\times 10^{18}$
  2. $3.125\times 10^{18}$
  3. $6.25\times 10^{12}$
  4. $3.125\times 10^{12}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

As charge is quantized. 

Total charge, $Q = ne$
$1$ coulomb $=ne \implies$ $n$ $= \dfrac{1} {1\cdot6\times10^{-19}}$

 
 $n$ $=6\cdot25\times10^{18}$

Multiple choice physics static electricity properties of charges charge properties of charge

There are $4\times { 10 }^{ 23 }$ atoms in a metal sphere. If one electron is removed from $0.1\%$ of atoms, what will be the charge on the sphere?

  1. $-6.4C$
  2. $64C$
  3. $0.64C$
  4. $-64C$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Given, 

$n=4\times 10^{23}\times 0.1$%

$n=4\times 10^{23}\times \dfrac{0.1}{100}=4\times 10^{20}$

$e=1.6\times 10^{-19}C$

The charge is quantised, $q=ne$

$q=4\times 10^{20}\times 1.6\times 10^{-19}=64C$

The electron is negative charge particle.

So,$q=-64C$

The correct option is D.
Multiple choice physics static electricity properties of charges charge properties of charge

$\displaystyle \frac {4}{25}$ Coulomb of charge contains .......... electrons

  1. $10^{15}$
  2. $10^{18}$
  3. $10^{20}$

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

The formula for quantization of charge is given as q=ne.
where q is the amount of charge in Columbu's, n is the number of charges and e is the charge on the electron.
In this case, q=4/25 C
So, e = $1.6\times { 10 }^{ -19 }C$.
n can be calculated as n=q/e = $\frac { 4 }{ 25 } \times [\dfrac { 1 }{ 1.6\times { 10 }^{ -19 }C } ]\quad =\quad { 10 }^{ 18 }$ which is the number of electrons.
Hence, 4/25 Coulomb of charge contains ${ 10 }^{ 18 }$ electrons.

Multiple choice physics static electricity properties of charges charge properties of charge

The number of electrons for one coulomb of charge are:

  1. $\displaystyle 6.25\times { 10 }^{ 23 }$
  2. $\displaystyle 6.25\times { 10 }^{ 21 }$
  3. $\displaystyle 6.25\times { 10 }^{ 18 }$
  4. $\displaystyle 6.25\times { 10 }^{ 19 }$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

1 electron carries a charge of $1.6 \times 10^{-19}$ coulomb 

So, No.of electron in one coulomb
$\dfrac{1}{1.6 \times 10^{-19}} = \dfrac{10^{19}}{1.6} = 6.25 \times 10^{18}$

Multiple choice physics static electricity properties of charges charge properties of charge

How many electrons make up a charge of $\displaystyle 20\mu C$ ?

  1. $\displaystyle 1.25\times { 10 }^{ 14 }$
  2. $\displaystyle 2.23\times { 10 }^{ 14 }$
  3. $\displaystyle 3.25\times { 10 }^{ 14 }$
  4. $\displaystyle 5.25\times { 10 }^{ 14 }$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Charge on an electron $= 1.6 \times 10^{-19}$coulomb

no of electrons required $ = \dfrac{20 \times 10^{-6}}{1.6 \times 10^{-19}} = 1.25 \times 10^{14}$

Multiple choice physics static electricity properties of charges charge properties of charge

How many electronic charges form 1 coulomb?

  1. $9.1\times 10^{-31}$
  2. $1.6\times 10^{18}$
  3. $62.5\times 10^{17}$
  4. $1.76\times 10^{11}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$q=ne$
$\therefore n=\dfrac {q}{e}$
Given $q=1C$
$e=-1.6\times 10^{-19}C$
$n=\dfrac {1C}{1.6\times 10^{-19}}$
$6.25\times 10^{18}$ or $62.5\times 10^{17}$

Multiple choice chemistry changes - physical and chemical effects of oxidation reactions in daily life corrosion of metals electroplating and its application

Number of Faradays involved in the net reaction of Lead accumulator is __________.

  1. 1

  2. 0.5

  3. 2

  4. cannot be predicted
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For lead accumulator battery, the oxidation reaction at anode  requires two moles of electrons. Similarly, the reduction reaction at cathode  requires two moles of electrons. Hence, the number of Faradays involved in the net reaction of Lead accumulator is 2.
Note: 1 Faraday is equal to the amount of charge on 1 mole of electrons.

Multiple choice chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

Given,
$E _{Ag^{+}/Ag}^{\circ}  = +0.80V, E _{Co^{2+}/Co}^{\circ} = -0.28 V, E _{Cu^{2+}/Cu}^{\circ} = +0.34 V, E _{Zn^{2+}/Zn}^{\circ} = -0.76V$, 
Which metal will corrode to greater extent?

  1. $Ag$
  2. $Cu$
  3. $Co$
  4. $Zn$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Metal having much more positive potential will Oxidise less easily and coorrode slowly and vice-versa. So, Zinc will corrode fastly.

Multiple choice

What is the typical voltage range of a lithium-ion battery cell?

  1. 1.5-2.5 V

  2. 3.0-4.2 V

  3. 6.0-7.5 V

  4. 9.0-10.5 V
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The typical voltage range of a lithium-ion battery cell is between 3.0 and 4.2 volts.

Multiple choice

What is the main component of a lithium-ion battery's positive electrode?

  1. Lithium cobalt oxide

  2. Lithium nickel manganese cobalt oxide

  3. Lithium iron phosphate

  4. Lithium titanate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The main component of a lithium-ion battery's positive electrode is lithium cobalt oxide.

Multiple choice

What is the electrolyte used in lithium-ion batteries?

  1. Lithium hexafluorophosphate in an organic solvent

  2. Sodium hexafluorophosphate in an organic solvent

  3. Potassium hexafluorophosphate in an organic solvent

  4. Magnesium hexafluorophosphate in an organic solvent
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The electrolyte used in lithium-ion batteries is lithium hexafluorophosphate in an organic solvent.

Multiple choice

Which type of flow battery utilizes vanadium ions as the active species?

  1. Zinc-Bromine

  2. Iron-Chromium

  3. Vanadium Redox

  4. Sodium-Sulfur
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Vanadium Redox batteries use vanadium ions in different oxidation states to store energy.