Chemical elements
    Physical Properties
    Chemical Properties
      Sodium hydride
      Sodium fluoride
      Sodium hydrogen fluoride
      Sodium chloride
      Sodium bromide
      Sodium iodide
      Sodium hypochlorite
      Sodium chlorate
      Sodium hypobromite
      Sodium bromate
      Sodium hypoiodite
      Sodium iodate
      Sodium periodates
      Sodium monoxide
      Sodium peroxide
      Sodium hydroxide
      Sodium perhydroxide
      Sodium monosulphide
      Sodium polysulphides
      Sodium hydrogen sulphide
      Sodium sulphite
      Sodium hydrogen sulphite
      Sodium potassium sulphite
      Sodium pyrosulphite
      Sodium sulphate
      Sodium hydrogen sulphate
      Sodium monopersulphate
      Sodium pyrosulphate
      Sodium persulphate
      Sodium thiosulphate
      Sodium dithionate
      Sodium trithionate
      Sodium tetrathionate
      Sodium pentathionate
      Sodium hyposulphite
      Sodium selenides
      Sodium selenite
      Sodium selenate
      Sodium sulphodiselenide
      Sodium tellurides
      Sodium tellurate
      Sodium nitride
      Sodium hydrazoate
      Sodium hydrazide
      Sodium hyponitrite
      Sodium nitrite
      Disodium nitrite
      Sodium nitrate
      Sodium phosphides
      Sodium dihydrophosphide
      Sodium hypophosphite
      Sodium phosphites
      Sodium dihydrogen phosphite
      Sodium hypophosphates
      Sodium orthophosphates
      Disodium hydrogen orthophosphate
      Sodium pyrophosphate
      Disodium dihydrogen pyrophosphate
      Sodium metaphosphate
      Sodium polyphosphate
      Sodium arsenites
      Sodium arsenates
      Sodium antimonate
      Sodium carbide
      Sodium carbonate
      Sodium hydrogen carbonate
      Sodium percarbonate
      Sodium cyanide
      Sodium thiocyanate
      Sodium silicates
      Sodium borates
    PDB 131d-1bli
    PDB 1bph-1d10
    PDB 1d11-1ej2
    PDB 1eja-1gb5
    PDB 1gb6-1goh
    PDB 1gq2-1ikp
    PDB 1ikq-1jz1
    PDB 1jz2-1kvs
    PDB 1kvt-1me8
    PDB 1mg2-1nsz
    PDB 1nta-1oyt
    PDB 1p0s-1qjs
    PDB 1qnj-1s5d
    PDB 1s5e-1tjp
    PDB 1tk6-1uxt
    PDB 1uxu-1vzq
    PDB 1w15-1xc6
    PDB 1xcu-1yf1
    PDB 1ygg-1zko
    PDB 1zkp-2afh
    PDB 2agv-2bhc
    PDB 2bhp-2cc6
    PDB 2cc7-2dec
    PDB 2deg-2ein
    PDB 2eit-2fjb
    PDB 2fld-2gg8
    PDB 2gg9-2h9j
    PDB 2h9k-2ien
    PDB 2ieo-2jih
    PDB 2jin-2omd
    PDB 2omg-2p77
    PDB 2p78-2q68
    PDB 2q69-2qz7
    PDB 2qzi-2v35
    PDB 2v3h-2vwo
    PDB 2vx4-2wig
    PDB 2wij-2x1z
    PDB 2x20-2xmk
    PDB 2xmm-2zfq
    PDB 2zfr-3a6s
    PDB 3a6t-3b1e
    PDB 3b2n-3bos
    PDB 3bov-3ccr
    PDB 3ccs-3d7r
    PDB 3d97-3e3y
    PDB 3e40-3erp
    PDB 3euw-3fgw
    PDB 3fh4-3g3r
    PDB 3g3s-3gxw
    PDB 3gyz-3hwt
    PDB 3hww-3ijp
    PDB 3imm-3k0g
    PDB 3k13-3l7x
    PDB 3l88-3max
    PDB 3mbb-3mr1
    PDB 3mty-3nu3
    PDB 3nu4-3ot1
    PDB 3ow2-3qwc
    PDB 3qx5-3tfr
    PDB 3tfs-3v6o
    PDB 3v72-4ag2
    PDB 4aga-4eae
    PDB 4ecn-4g8t
    PDB 4gdt-8icw
    PDB 8icx-9icy

hypochlorite, NaOCl

A solution of the hypochlorite in water is obtained by the action of chlorine on an aqueous solution of sodium hydroxide at a low temperature -

2NaOH+Cl2 =NaOCl+NaCl+H2O.

Solutions containing a high percentage of sodium hydroxide yield a concentrated solution of the hypochlorite, provided additional alkali is introduced periodically to maintain the concentration of the solution. Under these conditions, the sodium chloride produced by the reaction is precipitated, and a solution of hypochlorite obtained which reacts with hydrochloric acid to yield up to 49.2 grams of chlorine per 100 c.c. of solution. The temperature of the reaction should be maintained below 27° C., but the very concentrated solutions obtained lack stability, the hypochlorite changing to a mixture of chloride and chlorate, one molecule being oxidized at the expense of another. From very concentrated solution sodium hypochlorite separates as a solid hydrate, its composition approximating more nearly to that of the heptahydrate than the hexahydrate. It is a very unstable, hygroscopic substance, but dehydration in a current of dry air at reduced pressure converts it into the solid anhydrous hypochlorite, which melts about 45° C. It is less hygroscopic than the hydrate, and contains 40 to 60 per cent, of available chlorine.

When the turbid liquid formed by heating the heptahydrate at 20° C. is cooled slowly to the ordinary temperature, large greenish-yellow, very deliquescent crystals of the pentahydrate are formed. They melt at 27° C., and are stable at ordinary temperature in absence of air.

Sodium hypochlorite is also manufactured by the electrolysis of sodium-chloride solution without a diaphragm, the solution being less concentrated than that prepared by the chlorine process from sodium hydroxide, but free from the excess of alkali characteristic of that prepared by the older method. The process is carried out either in the apparatus designed by Kellner, or in that of Haas-Oettel, sodium chlorate being a by-product (v. infra). It is noteworthy that electrolysis of sodium-chloride solution with an alternating current also produces sodium hypochlorite.

Thomsen gives for the heat of formation of sodium hypochlorite in aqueous solution from its elements the value 83.36 Cal., Berthelot 84.7 Cal. For the molecular depression of the freezing-point in aqueous solution Raoult found the value 3.38° C.

In aqueous solution sodium hypochlorite finds technical application in the bleaching of paper, linen, cotton, and straw. In direct sunlight, concentrated solutions rapidly lose their activity. Storage in colourless bottles accelerates the rate of decomposition, and in brown bottles retards it. The stability of the solutions is much increased by complete exclusion of light.

© Copyright 2008-2012 by