[Chemistry Class Notes] on Sodium Hypochlorite Pdf for Exam

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Sodium hypochlorite is an ionic chemical compound with the formula NaOCl. It comprises sodium cation and hypochlorite anion. It is known by various other names such as antiform in, bleach etc. It is generally found in its pentahydrate state. As its anhydrous form is unstable and decomposes explosively. Sodium hypochlorite pentahydrate is a pale greenish-yellow solid which is stable and not explosive. It is widely used as a cleaning agent or as a bleach. 

Sodium Hypochlorite and its Formula

In liquid form, sodium hypochlorite is a strong oxidizing agent with a greenish or yellowish tint. Because it is the active element in bleach, it is generally referred to as bleach. One sodium (Na) atom, one chlorine (Cl) atom, and one oxygen (O) atom make up the chemical formula NaClO. The hypochlorite ion (ClO-) has an ionic interaction with the sodium (Na+) ion, as shown by its chemical structure. It has a molar mass of 74.44 grams per mol.

S. No.

IUPAC Name & Formula of Sodium Hypochlorite 

1.

  Empirical Formula 

  NaOCl

2.

  Molecular Formula 

  NaOCl or NaClO 

3.

  Skeletal formula

 ()

4. 

  IUPAC name 

  Sodium hypochlorite 

5. 

  Other general names 

  Antiformin, bleach, chloride of soda 

Structure of Sodium Hypochlorite

Sodium hypochlorite is a salt made up of sodium cation and hypochlorite anion. It is also known as the sodium salt of hypochlorous acid (HOCl). Its structure is given below –

()

Chemical properties: Sodium hypochlorite is a powerful oxidizer. It forms salts when it combines with protic acids like HCl, while also producing poisonous chlorine gas. It also forms hypochlorous acid when it combines with certain acids (HClO). It decomposes in water into sodium and chloride ions, as well as the potent oxidizer hydroxyl radical (OH.). In addition to sodium chloride and oxygen, NaClO decomposes into sodium chloride and oxygen.

  • Its molar mass is 74.4 g.mol-1.

  • Sodium hypochlorite pentahydrate is a greenish-yellow solid. 

  • It has chlorine-like and a sweetish odor. 

  • Its melting point is 18 ℃.

  • Its boiling point is 101 ℃.

  • It is soluble in water. 

  • Its density is 1.11 g.cm-3.

  • It is corrosive.

  • Sodium hypochlorite is unstable and explosive although sodium hypochlorite pentahydrate is stable at lower temperatures and non-explosive. 

  • It decomposes at high temperatures and forms sodium chlorate and sodium chloride. The reaction is given below –

3NaOCl(aq) → 2NaCl(aq) + NaClO3(aq)

  • It is used in the oxidation of starch. 

  • Oxidation of metals – Sodium hypochlorite reacts with metals and forms metal oxide by oxidizing them. The reaction is given below –

NaOCl + Mg ? MgO + NaCl

NH3 + NaOCl → NH2Cl + NaOH

NH2Cl + NaOCl → NHCl2 + NaOH

NH2Cl + NaOCl → NCl3+ NaOH

Uses of Sodium Hypochlorite 

Sodium hypochlorite is a very useful compound. It is used in many fields for various purposes. A few of its applications are listed below –

  • It is used as bleach. Household bleach solutions generally contain 3-8% of sodium hypochlorite by weight. 

  • It is used for cleaning purposes such as to remove mold stains, dental stains etc. 

  • It is used as a disinfectant. It has an antimicrobial ability which makes it very useful in hospitals as a disinfectant. It is used in Dakin’s solution as well. 

  • It has deodorizing and caustic effects which makes it even more useful for cleaning and laundry. 

  • It is used in the treatment of wastewater. 

  • Due to its effectiveness against pathogenic organisms, it is used in endodontic therapy. 

  • Soaps containing sodium hypochlorite are being used for the treatment of eczema in humans for decades. 

Sodium Hypochlorite acts as a bleaching agent and disinfectant for household as well as industrial purposes.

It’s also used as a disinfectant in water treatment facilities, swimming pools, some medical and dental procedures, in the food business as a deodorizer, in households as a deodorizer and cleaning agent, and in laundry detergents as a stain remover and bleach.

Sodium Hypochlorite: Summary in Tabular Form 

Sodium Hypochlorite 

Chemical formula 

NaOCl 

IUPAC Name 

Sodium hypochlorite 

Other names 

Antiformin, bleach, chloride of soda 

Molar mass 

74.4 g/mol

Melting point 

18 ℃

Boiling point 

101 ℃

Density 

1.11 g.cm-3

Appearance 

Greenish-yellow solid 

Odor 

Chlorine like smell 

State at STP

Liquid (solid for pentahydrate)

Solubility in water 

It is soluble in water (29.3 g/100ml)

Preparation 

By chlorination – 

Cl2 + 2NaOH ? NaCl + NaOCl + H2O

By calcium hypochlorite – 

Na2CO3 + Ca(OCl)2 ? CaCO3 + NaOCl

By electrolysis of brine (concentrated solution of NaCl and water)

By ozone and sodium salt –

NaCl + O3 ? NaOCl + O2

Main properties 

Its bleaching and deodorizing properties. 

Main use 

As a disinfectant and cleansing agent. 

Disadvantage 

Corrosive 

Difficulty in storage

This ends our coverage on the topic “Sodium hypochlorite”. We hope you enjoyed learning and were able to grasp the concepts. We hope after reading this article you will be able to solve problems based on the topic. If you are looking for solutions of NCERT Textbook problems based on this topic, then log on to website or download Learning App. By doing so, you will be able to access free PDFs of NCERT Solutions as well as Revision notes, Mock Tests and much more.

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