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What are Electrolytes

Some chemical compounds play an important role in cells in the body to function allowing the body to work these are called as electrolytes.

Electrolytes are allowing cells that generate energy and maintain the stability of their wall. They also involve in generation of electricity, contraction of muscles and move with water and fluids within the body. A variety of hormones control the activity and concentration of electrolytes in the body. These electrolytes are mainly secreted by the kidney and adrenal glands like rennin, angiotensin, aldosterone and antidiuretic hormone.

  • The amount of sodium, potassium and water in bloodstream monitors by some sensors located in kidney cells.
  • During dehydration of body, the stimulation of thirst mechanism also keeps electrolyte concentrations in balance.
  • Electrolytes maintain the voltage across the cell membranes of nerve, heart and muscle cells which further carry electrical impulses such as nerve impulses, muscle contractions across themselves and to other cells.
  • During our regular activities like exercise, we lose the balance of electrolytes in our sweat.
  • The concentration of electrolytes must be balanced by taking sports drinks which have sodium chloride or potassium chloride added with sugar and flavors to them.
  • Electrolyte drinks are also helpful during chronic vomiting or diarrhea in infants/children. As in these diseases, children lose electrolytes which must be replaced to prevent dehydration and seizures.


Define Electrolytes

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"Substances like acid, base and salts which can conduct electricity in their aqueous solution due to ionization are known as electrolytes."

The presence of ions in solution is responsible for the conduction and when the current passes through the wires, it shows the movement of free electrons through wires. 

The conduction is because of electrically charged ions which can migrate to the oppositely charged electrodes under the influence of a voltage. This process of dissociation and flow of ions in an aqueous solution of an electrolyte is known as electrolysis.

For example
, the electrolysis of sodium chloride in its aqueous solution gives sodium and chloride ion in solution. These ions get a discharge on electrodes and form a mixture of hydrogen and chlorine gas with an aqueous solution of sodium hydroxide. The electrolysis process of sodium chloride can be written as

2NaCl(aq) + 2H2O(l) $\overset{Electrolysis}{\rightarrow}$ 2Na+(aq) + 2OH-(aq) + H2(g) + Cl2(g)

There are many electrolytes present in the human body such as sodium, magnesium, calcium, potassium, chloride ion and bicarbonate ions. These electrolytes involve in various functions of our cells and our organs.

Main Electrolytes in Body Fluid

  • Out of these electrolytes, potassium, sodium and chloride ions are most essential electrolytes.
  • They are also found in our daily diet like potassium is found in banana, spinach, cantaloupe and skim milk.
  • The imbalance of electrolytes in the body can be responsible for many disorders. Like low concentration of potassium creates muscles cramps and weakness.
  • Sodium and chloride ions are mainly provided by table salt that is sodium chloride. The sodium ion is mainly found in plasma fluid outside of cells. 
  • It regulates the total amount of water in the body and the transmission of sodium into and out of individual cells also plays an important role in critical body functions.

Examples of Electrolytes

The following are few examples of electrolytes -
  • Hydrochloric acid (HCl)
  • Nitric acid (HNO3)
  • Sulfuric acid (H2SO4)
  • Hydrobromic acid (HBr)
  • Hydroiodic acid(HI)
  • Perchloric acid (HClO4)
  • Acetic acid (CH3COOH)
  • Carbonic acid (H2CO3)
  • Ammonia (NH3)
  • Lithium hydroxide (LiOH)
  • Sodium Hydroxide (NaOH)
  • Potassium Hydroxide (KOH)
  • Rubidium Hydroxide (RbOH)
  • Cesium Hydroxide (CsOH)
  • Calcium Hydroxide (Ca(OH)2)
  • Strontium Hydroxide (Sr(OH)2)
  • Barium Hydroxide (Ba(OH)2)

List of strong electrolytes

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Some electrolytes such as potassium chloride, sodium hydroxide, sodium nitrate are completely ionized in their constituent ions in solution. These electrolytes are known as strong electrolytes. In other words, strong electrolytes are 100% dissociated in their aqueous solution.

Their dissociation reactions are written with a single arrow directed to the right. Generally strong acids like sulfuric acid, nitric acid, strong bases like potassium hydroxide and salts are strong electrolytes.

For example:

KCl(aq) $\to$ K+(aq) + Cl-(aq)
NH4NO3(aq) $\to$NH4+(aq) + NO3-(aq)
HNO3(aq) $\to$ H+(aq) + NO3-(aq) 
NaOH(aq) $\to$ Na+(aq) + OH-(aq)

Strong Electrolytes

Strong electrolytes like salts are composed of oppositely charged ions. In the solid state, these ions are held by strong electrostatic forces of attractions. When these electrolytes are dissolved in water, the attraction forces between ions are highly weakened due to a high dielectric constant of water that is 80.

For example
, when we dissolved sodium chloride in water, the electrostatic force of interaction between ions reduced by factor 80 and facilitate the free movement of ions. These free ions get stabilized by salvation process with water.

In solvation process, sodium and chloride ions are surrounded by water molecules due to ion-dipole interactions. Solvation with water molecules is also called as hydration.

Solvation Process

Some common strong electrolytes are as follows.

 CategoryElectrolytes Chemical formula
 Strong acid Chloric acid   HClO3
 Hydrobromic acid  HBr
 Hydrochloric acid  HCl
 Nitric acid  HNO3
 Perchloric acid  HClO4
 Strong base  Potassium hydroxide  KOH
 Lithium hydroxide  LiOH
 Sodium hydroxide  NaOH
 Calcium amide  Ca(NH2)
 Sodium hydride  NaH
 Salts  Sodium nitrate  NaNO3
 Copper sulphate  CuSO4
 Potassium chloride  KCl
 Calcium chloride  CaCl2
 Sodium bicarbonate  NaHCO3

List of Weak Electrolytes

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Electrolytes which are weakly ionized in their aqueous solution are called as weak electrolytes. In the aqueous solution of weak electrolytes, the constituent ions are in equilibrium with undissociated molecules of electrolytes. 

Due to partial dissociation of electrolytes, the number of ions in a given volume of the solution almost remains same for a large change in the concentration. The chemical equations for the ionization or dissociation of weak electrolytes are written with double arrows ($\leftrightharpoons $). 

For example, the dissociation of acetic acid can be written as follows.

CH3COOH + H2O $\to$ H3O+ + CH3COO-

Dissociation of Weak Electrolytes
Such type of equilibrium exists between ions and unionized molecule is called as ionic equilibrium. The fraction of molecules dissociates can be represented by using degree of dissociation. Generally weak acids and bases are good examples of weak electrolytes. 

Some weak electrolytes are listed in given table.

S.No  Weak electrolyte  Chemical formula 
 1  Acetic acid  CH3COOH
 2  Hydrocyanic acid  HCN
 3  Ammonium hydroxide  NH4OH
 4  Ammonia  NH3
 5  Hydrofluoric acid  HF
 6  Carbonic acid  H2CO3
 7  Boric acid  H2BO3
 8  Nitrous acid  HNO2
 9  Lactic acid  C3H6O3
 10  Pyridine  C5H5N
 11  Ethylamine  C2H5NH2
 12  Dimethyl amine  (CH3)2N
 13  Glycine  C2H5NO2
 14 Trimethyl amine (CH3)3N
 15 Alanine C3H7NO2
 16 Oxalic acid (COOH)2
 17 Tap water H2O
 18 Phosphoric acid H3PO4
 19 Zinc sulphate ZnSO4
 20 Mercuric choride HgCl2
 21 Chromic acid H2CO3

List of Non-Electrolytes

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Non-electrolytes are the substances which cannot conduct electricity in their aqueous solution due to the absence of ions. They are generally polar or non-polar covalent compounds which can dissolve in water as molecules instead of ions. As covalent compounds contain covalent bonds between bonded atoms, therefore cannot be ionized in their solution and they exist in the form of a molecule only. 

For example Sugar (C12H22O11), alcohols are soluble in water but remain in molecular form only.
C12H22O11(s) $\overset{H_2O}{\rightarrow}$ C12H22O11(aq)

Some common non-electrolytes are as follows:

S.No  Non-electrolyte  Chemical formula 
 1  Sucrose  C12H22O11
 2  Glucose  C6H12O6
 3  Ethanol  C2H5OH
 4  Methanol  CH3OH
 5  Carbon tetrachloride  CCl4
 6  Carbon disulphide  CS2
 7  Kerosene  Hydrocarbon
 8  Chemically pure water H2
 9  Urea  NH2CONH2
 10  Dichloromethane  CH2Cl2
 11  Glycerol  C3H8O3
 12 Methylsulfonylmethane (CH2)2SO2
 13 Carbon dioxide CO2
 14 Oxygen O2
 15 Sulphur dioxide SO2

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