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Why sodium hypochlorite solution?

Sodium hypochlorite, commonly known as bleach, is most frequently used as a disinfecting agent. It is a broad-spectrum disinfectant that is effective for the disinfection of viruses, bacteria, fungi, and mycobacterium. We can easily make it by using common salt.The Centers for Diseases Control and Prevention (CDC) and the World Health Organization recommend using a bleach solution as one way to disinfect areas contaminated with the novel coronavirus.(

Need of project: 
We purchase several necessary things such as vegetables, feed of animals, groceries from the market but we can not be sure that these purchased things are disinfectant.So we had prepared a sodium hypochlorite solution which we can use at home to disinfect. We use this solution for surface sterilization and also for body disinfection. Preparation of sodium hypochlorite (NaOCl) by using common salt   (NaCl) by electrolysis process.

Electrolysis Process:
Electrolysis is a method of separating bonded elements by passing an electric current through them. An ionic compound salt is dissolved in water, so that its ions are available in the liquid.

● An electrical current is applied between a pair of inert electrodes immersed in the liquid. Each electrode attracts ions which are of the opposite charge. Therefore, positively charged ions (called cations) move towards the cathode, while negatively charged ions (termed anions) move toward the anode. The energy required to separate the ions, and cause them to gather at the respective electrodes, is provided by an electrical power supply.  

 Image 2: Schematic diagram of electrolysis process

Chemicals: 1) Distilled water: 700ml, 2) Salt (NaCl) : 20gm
Technical specification:

Input voltageDC 15V, 2A
Operating temperature30-40°C
Rated power consumption 30 watt
Required time  1 hour

Kit design:

 Image 3: Kit design on solid works

Requirement of material and specification:

Sr. No.Material description Specification Quantity 
1Glass jar Glass or polypropylene 1
2Carbon Rod
Carbon or graphite rod2
3Salt Ionised salt 20gm
4Circular frame7cm diameter 1
5Adaptor 15V, 2A1
6Water Distilled water700ml
 Image 4: Required materials for electrolysis process


  1. 2H2O(l) + 2NaCl → H2(g) + Cl2(g) + 2NaOH(l)
  2. 2NaOH + Cl2→ NaCl + NaOCl + H2O


 For the preparation of 0.8% NaOCl required 20 gm of NaCl in 700ml of distilled water.(According to the calculations followed by reaction.)

Faraday’s law states that the mass of substance deposited is directly proportional to the quantity of electricity.(

NaCl            +    H2O        +    2e          =  NaOCl    

35 lbs          + 15 gal         + 2.5 kWh   = 0.8 % NaOCl

1587. 57 gm + 56.7812 lit + 2.5 kWh   = 0.8 % NaOCl

Dividing 8 to equation 

198.45 gm    + 7.09765 lit  + 312.5 Wh  =  0.8 % NaOCl

Dividing 10 to equation 

19.84 gm     + 0.70965 lit   + 31.25 Wh  = 0.8 % NaOCl

We have to find moles of solution,

 1 mol = 6.02214076×1023 

For NaCl 58.5 gm

58.5 gm  = 1 mole = 6.023×1023  

19.84 gm =      ?

x= 19.84 × 6.023 ×1023 / 58.5

  X = 0.33 moles of NaCl

We have to find moles of electrons

1 faraday = 96500 C

1 electron = – 1.9 × 10-19 

 1 Faraday charge = 1 mole of e-

1 F = 6.023 × 1023  electron

     = 1 mole of e-

1 A = 6.24 × 1018 electron charge / second 

1A = 1C\1 second ( we use 2A current) 

1A = Q / s

We have to calculate moles of charge

     = 2 × 3600 × 6.024 ×1018 / 6.023 × 1023 

     = 0.07471 moles of electron flow

For NaOCl 74.5

74.5 gm    =   1 mole

    ?          =   0.07471 mole

            X = 5.5658 gm 

But we required 2 electrons 

5.5658 / 2 =2.782 moles

2.782 = 700 ml

  ?     = 1000 ml

X = 1000 × 2.782 / 700

3.9756% of NaOCl

20 gm  + 700 ml   + 31 Whr     = 0.8 % NaOCl
So, 0,8% of NaOCl required 20 gm of NaCl, 5180 C charge, 2A current, 15 volt and time will be 1 hour. 

Usage guidelines:  

Step 1: Take the beaker or pot and fill it up with 700ml fresh water and Add 19-20 gm of common salt in it.

Image 4: Measure salt and water for the process    

Step 2: Stir it, until salt is completely dissolved in water.

Image 5: stir the solution 

Step 3: Fix carbon rod in circular frame using glue gun and connect to output supply of adapter. 

Image 7: Fix carbon rod in circular frame.

Step 4: Pour the solution in a glass jar and fit a circular frame with a rod on the glass jar.

Image 8: Electrode dip in solution and connect to the adapter.

Step 5: Give the power supply to the carbon rod for one hour.

Step 6: During the reaction, the color of the solution will change and we get a final yellowish-green solution.(Note: Check pH before starting the electrolysis reaction and after the completion of the reaction. It should be between the 9-11 pH range.

Image 10: Sodium Hypochlorite solution

Step 7: Now we can use this solution to wash vegetables, fruits etc.

Image 11: Application of the solution

Result:Solution of sodium hypochlorite has been prepared which is concluded by strong chlorine odour, yellowish-green colour and pH of solution is 9 to 11 .

Bill of material:

Sr. No. Material Cost (Rs.)
1Glass jar 200
2Carbon rod40
4Circular frame 30


  1. To wash vegetables, fruits, feed animals.
  2. To clean the surface of the table,furniture etc.
  3. It is rarely used as an antiseptic. 
  4. Used as a disinfectant for treating potable water (lower concentration). 
  5. In hospitals as a high-level disinfectant.
  6. Bleaching agents in the textile, detergents, and paper and pulp industries.
  7. An oxidizing agent for organic products.


  1. Use on the outer surface of vegetables, fruits etc. 
  2. Do not spray NaOCl on your face.
  3. Keep kit away when supply is on. 
  4. Unplug the device if you are not using it.
  5. Keep kit away from children.
  6. Keep kit away from heat and high temperature


  1. Reduce the cost of disinfectant solution.
  2. Reduces harmful chemicals, odour, bacteria and virus from vegetables.
  3. Oxidizes harmful bacteria, viruses and pesticides from fruit. 
  4.  More convenient and easy
  5.  Portable
  6. Easy to handle