Electrochemistry VVI Questions 

 

 

Electrochemistry Objective Question 

Q.1. What do you mean by primary cell?

Ans- in primary batteries or cells, the electrode reactions cannot be reserved by an external electric energy source. In these cells, reactions occur only one and after use they become dead. Therefore, they are not chargeable. Some common examples are dry cell, mercury cell.

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Q.2. Write first law of Faraday’s law of electrolysis.

Ans- Faraday’s First law states that the amount of chemical reaction at an electric current is proportional to the quantity of electricity passed through the electrolyte ( in solution or in molten state).

 

Q.3. Define electrode and electrode potential.

Ans-

1. Electrode:- An electrode is a solid electric conductor that allows the passage of electric current through it self. Cathode (negative plate) and anode (positive plate).

2. Electrode Potential:– it is of potential difference developed between the electrodes and electrolyte or difference set up between the metal and its ions in the solution. It is called electrode potential.

 

Q.4. State and explain Faraday’s second law of electrolysis.

Ans- Faraday’s second law of electrolysis is that, when the same quantity of electricity is passed through Several electrolytes, mass of the substances deposited are proportional to their respective chemical equivalent or equivalent weight.

 

Q.5. What do you mean by Primary cell ?

Ans – In primary batteries or cells, the electrode reactions cannot be reversed by an exterrnal electric energy source. In these cells, reactions occur only once and after use they become dead. Therefore, they are not chargeable. Some common examples are dry cell, mercury cell.

 

Q.6. Define electrode and electrode potential.

Ans – Electrode – An electrode is a solid electric conductor that allows the passage of electric current through itself. Electrode are of two types, cathode (negative plate)  and anode (positive plate).

Electrode potential – It is the potential  difference developed between the electrodes and its electrolyte or it is the difference set up between the metal and its ions in the solution, it is called electrode potential.

 

Q.7. State and explain Faraday’s 2nd law of electrolysis.

Ans – Faraday’s second law of electrolysis states that, when the same quantity of electricity is passed through several electrolytes, the mass of the substances deposited are proportional to their respective chemical equivalent or equivalent weight.

 

Q.8. What is salt bridge? What are its uses ?

Ans – Salt bridge – When two solution in an electrochemical cell are kept apart through an arrangement, the arrangement is called salt-bridge. 

Salt bridge carries out two important functions ;

(1) It completes the circuit

(2) It maintains the electrical neutrality of the solution in the half cells.

 

Q.9. Where is electrolysis used ?

Ans – Electrolysis is mainly used in ;

(1) Electro-plating i.e. thin coating of desire metal over some other metal.

(2) Electro-refining i.e. purification of metals.

 

Q.10. State colligative properties of dilute solution. Write down the different types of colligative properties.

Ans – There are four main colligative properties;

(1) Relative lowering in Vapour pressure

(2) Elavation in boiling point

(3) Depression in freezing point

(4) Osmotic pressure

All the above said colligative properties (C.P) are directly proportional to the concentration i.e. 

C.P ∝ concentration

Therefore, value of all the colligative properties decreases with the dilute e.g. a pure liquid has zero-concentration and will show maximum vapour pressure means relative lowering in V.P is zero, or elevation in boiling point is zero.

 

Electrochemistry Objective Questions 

Q.1. pH of water is-

(a) 1

(b) 4

(c) 3

(d) 7

Ans – 7

 

Q.2. One Faraday electricity is equal to how much Coulombs ?

(a) 96550 

(b) 96500

(c) 96000

(d) 95500

Ans – 96500

 

Q.3. When one Faraday of electric current is passed, the mass deposited is equal to –

(a) One gram equivalent

(b) One gram mole

(c) Electrochemical equivalent

(d) Half gram equivalent

Ans – One gram equivalent

 

Q.4. Faraday’s law of electrolysis is related to –

(a) Atomic number of cation

(b) speed of cation

(c) Speed of anion

(d) Equivalent weight of element

Ans – Equivalent weight of element

 

Q.5. Fused NaCl on electrolysis gives………….. on cathode.

(a) Chlorine

(b) Sodium

(c) Sodium amalgam

(d) Hydrogen

Ans – Sodium

 

Q.6. If 96500 coulomb of electricity is passed through CuSo4 solution, it will liberate –

(a) 63.5 g Cu

(b) 31.76 g Cu

(c) 96500 g Cu

(d) 100 g Cu

Ans – 31.76 g Cu

 

Q.7. Which of the following metals on reacting with acid solution gives hydrogen gas ?

(a) Na

(b) cu

(c) Al

(d) Fe

Ans – (a) , (c) , (d)

 

Q.8. The cell used in Apollo mission was –

(a) Leclanche cell

(b) Daniell cell

(c) voltaic cell

(d) Bacon cell

Ans – Bacon cell

 

Q.9. Fuel cells are preferred to other energy producing devices in space because of –

(a) High efficiency

(b) Pollution free

(c) Less weight

(d) All of these

Ans – All of these

 

Q.10. The main factors which affect corrosion is/are –

(a) Potential of metal in electrochemical series

(b) Presence of Co2 in water

(c) Presence of impurities in metal

(d) Presence of protective coating

Ans – (a) , (b) and (c)