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 metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

 The standard electrode potentials ${\text{E}} _{{{\text{I}} _2}/{1^ - }}^ \circ ,{\text{E}} _{{\text{B}}{{\text{r}}^ - }/{\text{B}}{{\text{r}} _2}}^ \circ $ and ${\text{E}} _{{\text{Fe/F}}{{\text{e}}^{2 + }}}^ \circ $ are respectively $ + 0.54{\text{V,}} - 1.09{\text{V}}$ and 0.44 V. On the basis of the above data which of the following process is nonspontaneous?

  1. ${\text{B}}{{\text{r}} _2} + 2{{\text{I}}^ - }\;{\text{2B}}{{\text{r}}^ - } + {{\text{I}} _2}{\text{ }}$
  2. ${\text{Fe}} + {\text{B}}{{\text{r}} _2}\;{\text{F}}{{\text{e}}^{2 + }} + 2{\text{B}}{{\text{r}}^ - }$
  3. ${\text{Fe}} + {{\text{I}} _2}{\text{ F}}{{\text{e}}^{2 + }} + 2{{\text{I}}^ - }$
  4. ${{\text{I}} _2} + 2{\text{B}}{{\text{r}}^ - }2{{\text{I}}^ - } + {\text{B}}{{\text{r}} _2}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

the one which is having higher oxidation potential will undergo oxidation,

in D, $I^-$ is having lower reduction potential in comparison to $Br^-$, so has to undergo oxidation but in option D, it is getting oxidized.
hence, it is a nonspontaneous reaction.

Multiple choice physics electric current and its effects thermal effect of electric current heating effect of electric current effect of electric current

A copper voltameter is connected in series with a coil of resistance $10 \Omega $. When a steady current is passed through the circuit, $0.297 g$ of copper is found to be deposited at the cathode in $15 min$. The electrochemical equivalent of copper is $3.3 \times 10^{-7} kg C^{-}$. Heat liberated in the coil is:

  1. $900 J$
  2. $90 J$
  3. $9 J$
  4. $9 kJ$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$\displaystyle I = \frac {m}{Zt} = \frac {297 \times 10^{-6}}{3.3 \times 10^7 \times 15 \times 60}=1A$

$H = I^2Rt = 1 \times 10 \times 15 \times 60$
$=9000J = 9kJ$

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

One electron volt is equal to .......................

  1. $\displaystyle 1.6\times 10^{-19}$ Joule
  2. $\displaystyle 16\times 10^{-19}$ Joule
  3. $\displaystyle 1.6\times 10^{-10}$ Joule
  4. $\displaystyle 1.6\times 10^{-9}$ Joule
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

One electron volt is the energy gained by an electron accelerated through a potential difference of 1 volt, which is 1.6 * 10^-19 Joules.

Multiple choice chemistry amines introduction to diazonium salts structure, preparation and physical properties of diazonium salts diazonium salts

In an analytical determination of arsenic, a solution containing arsenious acid, $ H _{3}AsO _{4},$ KI and a small amount of starch is electrolysed. The electrolysis produces free $I _{2}$ from $ I^{-}$ ions and the $ I _{2}$ immediately oxidizes the arsenious acid to hydrogen arsenate ion, $ HAsO _{4}^{2-}.$
$ I _{2}+H _{3}AsO _{3}+H _{2}O \rightarrow 2I^{-} + HAsO _{4}^{2-}+4H^{+}$
When the oxidation of arsenic is complete, the free iodine blue colour. If during a particular run, it takes 96.5 s for a current of 10.0 mA to give an end point (indicated by the blue colour),how many g of arsenic are present in the solution. (As = 75)

  1. $ 6.3 \times 10^{-4} g$
  2. $1.26 \times 10^{-4}g$
  3. $ 3.15 \times 10^{-5}g$
  4. $ 6.3 \times 10^{-5}g$
Reveal answer Fill a bubble to check yourself
D Correct answer
Multiple choice
  1. In electrolysis of water, oxygen gets deposited at the

  1. cathode

  2. anode

  3. at both the electrodes

  4. there is no oxygen released
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In water electrolysis, oxygen gas is produced at the anode (positive electrode) and hydrogen at the cathode (negative electrode). This follows from oxidation-reduction principles: water molecules lose electrons at the anode to form oxygen. The '11.' prefix appears to be a question number artifact.

Multiple choice bio-chemistry plant physiology active transport and passive transport types of plant transport atp

If the amount of an ion absorbed by a root hair cell at $0^{0}C$ is 5 gm and at $20^{0}C$ is 20 gm. The amount of this ion absorbed actively should be

  1. 25 gm

  2. 20 gm

  3. 15 gm

  4. 5 gm
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

At 0 degree Celsius the respiration rate will be zero. At 20 degree Celsius only the respiration process will take place. Hence, the 5 gm initially absorbed is due to physical diffusion of mineral ions from a region of high to low concentration. Later on, respiration occurs, then extra 15 grams are actively absorbed.

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

A gold coin has a charge of $+10^{-4} C$. The number of electrons removed from it is:

  1. $10^6$
  2. $625 \times 10^{12}$
  3. $1.6 \times 10^{-25}$
  4. $1.6 \times 10^{13}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The total charge of electrons removed from the coin would be equal to the positive charge acquired by the coin.

Thus, $10^{-4}C=n\times 1.6\times 10^{-19}C$
$\implies n=625\times 10^{12}$

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

Which component of a flow battery is responsible for the electrochemical reactions?

  1. Electrodes

  2. Separator

  3. Electrolyte

  4. Current Collector
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Electrodes in a flow battery undergo redox reactions to store and release energy.

Multiple choice

What is the name of the equation that relates the electromotive force (EMF) of an electrochemical cell to the standard reduction potentials of the half-reactions?

  1. Nernst Equation

  2. Arrhenius Equation

  3. Henderson-Hasselbalch Equation

  4. Clausius-Clapeyron Equation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Nernst equation relates the EMF of an electrochemical cell to the standard reduction potentials of the half-reactions, taking into account the temperature and concentrations of the reactants and products.

Multiple choice

What is the standard reduction potential of the hydrogen electrode?

  1. 0 V

  2. 1 V

  3. -1 V

  4. 2 V
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The standard reduction potential of the hydrogen electrode is defined as 0 V, serving as the reference point for all other reduction potentials.

Multiple choice

What is the relationship between the EMF of an electrochemical cell and the Gibbs free energy change of the reaction?

  1. The EMF is equal to the Gibbs free energy change divided by the Faraday constant.

  2. The EMF is equal to the Gibbs free energy change multiplied by the Faraday constant.

  3. The EMF is equal to the Gibbs free energy change.

  4. The EMF is not related to the Gibbs free energy change.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The EMF of an electrochemical cell is related to the Gibbs free energy change of the reaction by the equation EMF = -ΔG / nF, where EMF is the electromotive force, ΔG is the Gibbs free energy change, n is the number of moles of electrons transferred, and F is the Faraday constant.