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

Sodium chlorate, NaClO3

When chlorine is passed into a hot solution of sodium hydroxide, the hypochlorite primarily formed changes into a mixture of chlorate and chloride, both salts crystallizing out:


3NaOCl =NaClO3+2NaCl.

The chlorate is purified from the chloride by fractional crystallization. In Muspratt's method magnesium oxide suspended in water is substituted for sodium hydroxide, the solution being concentrated after treatment with chlorine, and sodium carbonate added to precipitate the magnesium for further use. The sodium chlorate crystallizes from the mother-liquor. The salt is also formed from potassium chlorate by double decomposition with substances such as sodium hydrogen tartrate and sodium silicofluoride. as well as by the electrolytic decomposition of sodium-chloride solution under certain conditions.

Sodium chlorate is a colourless, crystalline substance, and exhibits trimorphism, forming crystals belonging to the cubic, hexagonal, and rhombic systems. For its melting-point Retgers gives 248° C., Foote and Levy 255° C., Smits 261° C., and Carnelley 302° C. The density at 15° C. is given by Bodeker as 2.289, by Retgers as 2.490, and by Le Blanc and Rohland as 2.996. The specific heat of the solid is given by Foote and Levy as 0.281, and of the fused salt as 0.581, the latent heat of fusion being 48.4 cal.

At 15° C., 100 grams of water dissolve 91 grams. Kremers gives the solubility-table:

Solubility of Sodium Chlorate, NaClO3.

Temperature, °C.01220406080100
Grams NaClO3 in 100 g. water8298.599123.5147175204

The saturated solution exhibits the remarkable phenomenon of having two boiling-points, 126° C. and 255° C., a property characteristic of some other readily soluble salts, exemplified by the nitrates of sodium, potassium, silver, and thallium. It is due to an increase with rise of temperature in the vapour-pressure of the solution up to a maximum greater than the atmospheric pressure, further rise of temperature being accompanied by a diminution in the vapour-pressure of the solution as the composition of the system tends to approximate to that of the solid phase.

For the heat of formation from the elements, Thomsen gives 86.7 Cal., and Berthelot 85.4 Cal. For the heat of solution at 10° C., Berthelot gives -5.6 Cal.

References are appended to investigations of the optical properties of the crystalline forms; to such properties of the aqueous solution as vapour-pressure, density molecular depression of the freezing-point, electric conductivity, and index of refraction; and to the solubility in ethyl alcohol.

Sodium perchlorate, NaClO4. - On heating sodium chlorate, besides the decomposition with evolution of oxygen, there is a partial conversion of the salt into perchlorate and chloride -

4NaClO3 = 3NaClO4+NaCl.

The salt can also be prepared by neutralizing perchloric acid with sodium hydroxide, but it is manufactured by the electrolytic oxidation of a 25 per cent, sodium-chlorate solution at 10° C., platinum electrodes and a high anode-potential being employed. This process finds application in the manufacture of potassium perchlorate, this salt being obtained from the sodium compound by the action of potassium chloride.

At ordinary temperature, sodium perchlorate crystallizes as the very deliquescent monohydrate, but above 50° C. as the anhydrous salt. Its deliquescent character hinders its technical application. The melting- point of the anhydrous salt is 482° C. On heating, it is decomposed into chloride and oxygen, a proportion of chlorate being simultaneously formed. From cryoscopic experiments with sodium sulphate as solvent, Lowenherz inferred the molecular formula to be NaClO4.

For the heat of formation from its elements, Berthelot gives 100.3 Cal., and for the heat of solution at 10° C., 3.5 Cal. The electric conductivity has been investigated by Ostwald and by Walden.

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