Recent questions tagged electrochemistry

Description : In a magnetic material, always there exist magnetic dipoles as well as monopoles. State True/False. a) True b) False

Last Answer : b) False

Description : In a static magnetic field only magnetic dipoles exist. State True/False. a) True b) False

Last Answer : a) True

Description : Ionic non polar solid dielectrics contain more than one type of atoms but no permanent dipoles. State True/False a) True b) False

Last Answer : a) True

Description : Why gold ,silver and pt are used in making ornaments?

Last Answer : Ans: Because these are nobel metals and therefore their rusting doesn,t occure and also these are very lustorous(shiny),so due to these qualities ,these are used for making ornaments.

Description : Why for chromium plating iron is firstly platted by copper or nickel?

Last Answer : Ans: Because chromium metal doesn’t adhere directly to the iron properly so it is firstly plated with nickel or copper.

Description : What is electroplating and what is its objective?

Last Answer : Ans:The process in which one metal is deposited at other electrolytically. It is very useful process and following are objective of electroplating. (a) Deposition of Nobel metals on inferior metals. (b) Protection of different metals from corrosion. (c) Repair of broken machinery.

Description : How could we prevent H+ ions to be discharged first than Na+ during electrolysis of aqueous solution of NaCl?

Last Answer : Ans: This could be prevented by using mercury cathode during this kind of electrolysis, because H+ ions need high voltage to be discharged at mercury cathode. In this way sodium got discharged at cathode despite H+ ions.

Description : During electrolysis of aqeous solution of NaCl, there are two type of anions are present Cl- and –OH, Cl- is discharged first than –OH,although it is present below Cl- in electrochemical series. Give reason.

Last Answer : Ans: During this electrolysis process Chloride ions come from NaCl, which is a strong electrolyte and ionize to large extent so concentration of chloride ions in solution will be high. ... chloride ions it is first discharged despite of its presence above than hydroxyl in electrochemical series.

Description : Why cation present below in electrochemical series can discharge before the elements present above them in an electrochemical cell?

Last Answer : Ans: This is because their ability to be reduced (reduction potential) is more than the cation present above them in electrochemical series. So they take electrons before the other cations and get discharged.

Description : What is modern theory about the existence of the ionic compounds in solid state?

Last Answer : Ans: According to modern theory these exist in form of ions even in solid state for example, sodium chloride exist as Na+ Cl- . Whereas according to the ionic theory it exists as NaCl.

Description : Why sulphuric acid is added to the water during electrolysis of water?

Last Answer : Ans: It is added to increase conduction of the water, because water is a weak electrolyte.

Description : In Down’s cell, why the reaction between sodium metal and chlorine gas must be avoided? And how could we prevent reaction between them?

Last Answer : Ans:In Down’s cell electrolysis of fused NaCl yields sodium metal and chlorine gas .If these are not separated these will react to form Nacl again. So to prevent these reaction in Down’s cell, we place a steel gauze between cathode and anode.

Description : Why carbon electrode is used during electrolysis of Nacl, instead of Pt electrode?

Last Answer : Ans: During electrolysis of Nacl, chlorine gas is produced at anode. Thus to avoid it’s reaction with platinum we use carbon electrode.

Description : Why an electrolyte in molten or fused state is electrically neutral?

Last Answer : Ans: Because the number of + ve charges and –ve charges are equal , so as a result an electrolyte appears to be neutral in nature.

Description : Why ionic compounds are non conductor in solid state and conductor in molten or fused state?

Last Answer : Ans: This is because in solid state there are no free ions and their free movement isn’t possible but in molten or fused state the free movement of ions is possible, so these can conduct electric current.

Description : What is “redox” reaction?

Last Answer : Ans: “The reaction in which both reduction and oxidation takes place is called redox reaction. Reduction: “Addition of electron in an atom”. Oxidation: “Removal of electron from an atom”.

Description : What is difference between electrolytic and voltaic cell?

Last Answer : Ans:In electrolytic cell a non-spontaneous redox reaction is carried out with help of electrical energy. Wherease In voltaic cell a spontaneous redox reaction generates the electrical energy.

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