Tag: applications of electrolysis

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Multiple choice chemistry chemical effects of electric current applications of electrolysis electroplating extraction of metals by electrolysis

If $Zn/Zn^{+2}$ electrode is diluted 100 times then the change in electromotive force will be :-

  1. increases of 59 mV

  2. decreases of 59 mV

  3. increases of 29.5 mV

  4. decreases of 29.5 mV
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Using the Nernst equation: E = E_cell - (0.059/n) * log(1/[Zn+2]). Diluting 100 times increases the concentration of the denominator in the log term, making the log term more negative, which increases the overall potential by (0.059/2) * log(100) = 0.059 V = 59 mV.

Multiple choice chemistry chemical effects of electric current applications of electrolysis electroplating extraction of metals by electrolysis

The process of depositing thin layer of a metal over an another metal with a help of electric current is called :

  1. electrorefining

  2. electroplating

  3. thermoplating

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Electroplating is the process of plating one metal onto another, for decorative purposes or to prevent corrosion of a metal. 

Multiple choice chemistry chemical changes applications of electrolysis electroplating extraction of metals by electrolysis

Which pair of electrolytes could not be distinguished by the products of electrolysis using inert electrodes.

  1. $\text{1M CuSO} _4$ solution, $\text{1M CuCl} _2$ solution
  2. $\text{1M KCl}$ solution, $\text{1M Kl}$ solution
  3. $\text{1M AgNO} _3$ solution, $\text{1M Cu(NO} _3) _2$ solution
  4. $\text{1M KCl}$ solution, $\text{1M NaCl}$ solution
  5. $\text{1M CuBr} _2$ solution, $\text{1M CuSO} _4$ solution
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Electrolysis of 1M KCl and 1M NaCl using inert electrodes both yield potassium or sodium ions remaining in solution while hydrogen gas is evolved at the cathode and chlorine gas at the anode, making their electrolysis products identical and indistinguishable.

Multiple choice chemistry chemical changes applications of electrolysis electroplating extraction of metals by electrolysis

On passing one friday of electric charge through a dilute solution of an acid, the volume of hydrogen obtained at S.T.P. is :

  1. 22400 ML.

  2. 1120 mL

  3. 2240 mL

  4. 11200 ML.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

One Faraday (96500 C) of charge deposits or releases 1 gram equivalent of a substance. For H2 gas (n=2), 1 Faraday releases 0.5 moles of H2. Volume at STP = 0.5 * 22400 mL = 11200 mL.

Multiple choice chemistry chemical changes applications of electrolysis electroplating extraction of metals by electrolysis

Electrolysis rules of Faraday's states that mass depends on electrodes is proportional to:-

  1. $m \propto I^2$
  2. $m \propto Q$
  3. $m \propto Q^2$

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

Faraday's first law of electrolysis states that the mass of a substance deposited is directly proportional to the quantity of electricity (charge Q) passed through the electrolyte.

Multiple choice chemistry chemical changes applications of electrolysis electroplating extraction of metals by electrolysis

The process of electrolysis is used in:

  1. extraction of metals

  2. electroplating

  3. refining of metals

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Answer is D.
Electrolysis has wide applications in industries. Some of the important applications are, as follows, 
(i) Production of hydrogen by electrolysis of water. 
(ii) Manufacture of heavy water. 
(iii) The metals like K, Mg, Al, etc., are obtained by electrolysis of fused electrolytes. 
(iv) Non-metals like hydrogen, fluorine, chlorine are obtained by electrolysis. 
(v) In this method pure metal is deposited at cathode from a solution containing the metal ions, etc. 
(vi) Compounds like NaOH, KOH, white lead, etc. are synthesised by electrosynthesis method.
(vii) Electroplating: The process of coating an inferior metal with a superior metal by electrolysis is known as electroplating. 
Hence, the options A, B and C are correct.

Multiple choice chemistry chemical changes applications of electrolysis electroplating extraction of metals by electrolysis

Electromeric effect involves the completer transfer of 

  1. $\sigma $ electorn
  2. $\pi $ electron

  3. proton
  4. Both $\sigma $ and $\pi $ electrons
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The electromeric effect is a temporary effect that involves the complete transfer of a shared pair of pi electrons to one of the atoms joined by a multiple bond on the demand of an attacking reagent. Sigma electrons are not involved in this process.