What is electrochemistry , Arrhenius theory and Ohms laws and more

 Electrochemistry:-

The branch of chemistry which deals with the study of relationship between electrical energy and chemical energy and interconversion of one form into another is called electrochemistry .

• Conductors :- The substances which allow the passage of electricity  through them them are called conductors .

                             The conductors can be broadly classified info two categories .

• Metallic conductors :- These are the metallic substances which allow the passage of electricity through them without undergoing any chemical charge.

Example :- Copper , Silver , aluminium etc.

• Electrolytes :- There are the substances which allowed the passage of electricity through their  aqueous solutions and also undergo chemical decomposition at some time .

example :- acids , bases, and salts 

Comparison of  Electrolytic and Metallic Conduction

 Metallic  Conduction

• The Chemical properties of the conductors do not charge. 

• Conduction through metals is carried by the movement of electrons . 

• It does not involve any transfer of mater . 

• It  shows increase in resistance with the increase in temperature .

• The conductivity of metals is generally high .

Electrolytic 

• Conduction through electrolytes is carried movement of ions .

• It involves chemical change resulting  in the decomposition  of  electrolytes .

• Electrolyte conduction increases with increases in temperature .

• It shows decrease in resistance with the increase in temperature .

• The conductivity of electrolytic solution is generally law.

Non Conductors :-  The  substances which do not allow the passage of  electricity through them are called insulators or  non - conductors . 

Non electrolytes :-  The substances  which  do not  conduct  electricity either in their  molten state or  through their  aqueous solution are called non electrolysis .

                                         ARRHENIUS THEORY OF IONISATION

• In solution all electrolytes are spontaneously  dissociated to  some extent , into  charged particles called  ions  , The ions carrying positive charge are called cations , While those carrying negative charge are called anions. 

                                               The process of spontaneous splitting  up of an  electrolyte into ions When dissolved in a solvent is called electrolytic dissolution or ionization  ,

• Cations are generally metallic radicals obtained by loss of electrons from the metallic atoms , while anions are non metallic atom or radicals obtained by gain of electrons by non metallic atoms or group of non metals.

• The total positive charge on the cations present in a solution is equal but opposite to the total negative charge present on the anions . Thus the solution of an electrolytes is neutral as a whole.

• The cations and anions present in a  solution are constantly ceaselessly re-uniting to from between the ionized and unionized molecules.

                                                      AB = A+  +   B -

                   Unionized molecules cation Anion 

   Thus ,  the process of electrolytic dissociation is a reversible process .

• The ions are free to move and under the influence of  electricity  , they  are directed towards oppositely charged electrodes . Cation move towards cathode while  anions move towards anode.

• The properties of electrolytes in solution are  the properties of the ions produced . 

• The electrolyte at a given dilution may not be completely ionized and the fraction of the total molecules ionized, is termed degree of ionization , 

Degree of ionization = No of  molecules dissociated into  ions / Total of  molecules taken 

• Electrolytes like mineral acids  alkalis  and most salts which give solutions with  high conductivities are called strong  electrolytes . 

• Electrolytes like most  organic acids bases water and  ammonium hydroxide which are poor conduction in solution are called weak electrolytes . 

• The conduction of an electrolytes solution , generally increases with the increase in temperature because the average  kinetic energy of the ions increase as temperature increase , 

  

Electrolytic conductance :- When a voltage is applied to the electrolyte dipped into an electrolyte solution. ions of the electrolyte move and therefore electric current follows  through the electrolytes to conduct electric current is termed as conductance or conductivity . 

Ohms Law :-

This low is obeyed  both by metallic as well as electrolytic  conductors . It state that The current flowing through a conductor is directly proportional to the potential difference across it . 

                                                          I samanupati V 

Where I is the current strength and V is the potential difference applied across the conductor  in volts 

or I = V / R or V = IR

Where R is the constant of proportionality and is known as resistance of the conductor , I t is expressed in ohms and is represented as ohm. , 

Resistance : -    It measures the obstruction to the  flow of  current the resistance of any conductor is directly proportional to the length and inversely proportional to the area  of cross section D so that 

                              R samanupati L / D or  R = P L / D 

Where P rho is the constant of proportionality and is called specific resistance or resistivity . the resistance depends upon the nature of material 

  

Conductance :- 

    It is measure of the ease with which current flows through a conductor  . It expressed as G . The reciprocal of the electrical resistance is called conductance . 

           

                     Thus , G = I / R 

Units :- the units of conductance are reciprocal ohm or mho .or siemens . 

Conductivity :-

                 The inverse of resistivity is called conductivity [specific conductance ] . It is represented by the symbol , k  [green kappa]

Equivalent Conductivity :-

 It  is defined as the conduction of a solution containing  1 gm equivalent of electrolyte such the entire solution is placed between two electrodes one centimetre apart. It is denoted by symbol eq . 

Molar Conductivity :- 

Molar conductivity is defined as the conductance of the solution containing one gram mole of the electrolyte . Such that the entire solution is placed between two parallel electrodes one centimetre apart. It is denoted by Am . Molar conductivity is related to conductivity k by the relation . 

Various of Molarity conductivity :

In general the conductance of an electrolysis solution  depends upon the following factors . 

• Nature of electrolyte :- The conductance of the solution depends upon the nature of electrolyte . they can be divided into two categories 

      Strong electrolytes:- An electrolyte which is completely ionised in aqueous solution is called strong electrolyte .

 

   Weak electrolytes :- An electrolytes which is not completely ionised in a queues solution is called weak electrolyte.

• concentration 
• Temperature