Chemical elements
  Zinc
    Isotopes
    Energy
    Production
    Application
    Physical Properties
    Chemical Properties
      Zinc Fluoride
      Zinc Chloride
      Zinc Oxychlorides
      Zinc Bromide
      Zinc Iodide
      Zinc Hypochlorite
      Zinc Perchlorate
      Zinc Bromate
      Zinc Iodate
      Zinc Periodate
      Zinc Oxide
      Zinc Hydroxide
      Zincates
      Zinc Peroxide
      Zinc Sulphide
      Zinc Hydrosulphite
      Zinc Thiosulphate
      Zinc Sulphite
      Zinc Sulphate
      Zinc Dithionate
      Zinc Tetrathionate
      Zinc Pentathionate
      Zinc Selenide
      Zinc Selenites
      Zinc Selenate
      Zinc Telluride
      Zinc Tellurate
      Zinc Chromite
      Zinc Chromate
      Zinc Dichromate
      Zinc Molybdate
      Zinc Tungstate
      Zinc Nitride
      Zinc Azide
      Zinc Amide
      Zinc Ammoniate
      Zinc Nitrite
      Zinc Nitrate
      Basic Zinc Nitrates
      Zinc Phosphide
      Zinc Hydrophosphide
      Zinc Hypophosphite
      Zinc Phosphite
      Zinc Thiophosphite
      Zinc Orthophosphate
      Zinc Pyrophosphate
      Ammonium Zinc Orthophosphate
      Zinc Thiophosphates
      Zinc Arsenide
      Zinc Arsenite
      Zinc Arsenates
      Zinc Metantimonate
      Thioantimony Salts of Zinc
      Zinc Carbonate
      Zinc Thiocarbonate
      Zinc Cyanide
      Zinc Thiocyanate
      Zinc Silicide
      Zinc Silicates
      Zinc Borates
      Zinc Perborate
    PDB 12ca-1ai0
    PDB 1aiy-1b6z
    PDB 1b71-1bs8
    PDB 1bsk-1cao
    PDB 1caq-1ctt
    PDB 1ctu-1de6
    PDB 1def-1dy0
    PDB 1dy1-1ed6
    PDB 1ed8-1exk
    PDB 1eyf-1fj9
    PDB 1fjg-1g0e
    PDB 1g0f-1gkq
    PDB 1gkr-1ha5
    PDB 1hbm-1hso
    PDB 1hsz-1i6v
    PDB 1i73-1im5
    PDB 1iml-1jcv
    PDB 1jcz-1jy8
    PDB 1jyb-1kh4
    PDB 1kh5-1kys
    PDB 1kzo-1llm
    PDB 1llu-1m7j
    PDB 1m9j-1mwo
    PDB 1mwq-1ndv
    PDB 1ndw-1nyq
    PDB 1nyr-1os4
    PDB 1os9-1p9w
    PDB 1paa-1pud
    PDB 1pv8-1q9l
    PDB 1q9m-1qv6
    PDB 1qv7-1r6o
    PDB 1r79-1ro9
    PDB 1ror-1sfo
    PDB 1sg0-1t3k
    PDB 1t4k-1tkh
    PDB 1tkj-1u0l
    PDB 1u10-1ums
    PDB 1umt-1v67
    PDB 1v6g-1vrq
    PDB 1vs0-1wew
    PDB 1wfe-1wwf
    PDB 1wwg-1xb1
    PDB 1xb8-1xpz
    PDB 1xq0-1y5w
    PDB 1y5x-1ylk
    PDB 1ylo-1z8r
    PDB 1z93-1zkx
    PDB 1zl6-258l
    PDB 2a03-2afo
    PDB 2afs-2atq
    PDB 2au3-2bfz
    PDB 2bg2-2c3a
    PDB 2c4r-2cij
    PDB 2cim-2czr
    PDB 2d0w-2djw
    PDB 2dkc-2e1b
    PDB 2e1s-2eer
    PDB 2eex-2em4
    PDB 2em5-2eoj
    PDB 2eok-2erq
    PDB 2esf-2fa7
    PDB 2fac-2fpx
    PDB 2fqp-2g84
    PDB 2g87-2gvf
    PDB 2gvi-2han
    PDB 2hap-2huc
    PDB 2hue-2imc
    PDB 2imr-2j65
    PDB 2j6a-2jq5
    PDB 2jr7-2kfn
    PDB 2kft-2l75
    PDB 2lgv-2nx9
    PDB 2nxa-2oc8
    PDB 2occ-2osm
    PDB 2oso-2p53
    PDB 2p57-2pow
    PDB 2ppb-2q8j
    PDB 2qa1-2qp6
    PDB 2qpj-2r71
    PDB 2r74-2sod
    PDB 2srt-2v86
    PDB 2v87-2vp7
    PDB 2vpb-2vyo
    PDB 2vz5-2wey
    PDB 2wfq-2wx0
    PDB 2wx1-2xam
    PDB 2xan-2xr9
    PDB 2xrg-2ytd
    PDB 2yte-2z30
    PDB 2z3g-2zet
    PDB 2zh0-3a32
    PDB 3a36-3aoi
    PDB 3at1-3bk1
    PDB 3bk2-3byr
    PDB 3byw-3cia
    PDB 3ciz-3d08
    PDB 3d09-3dbu
    PDB 3dc3-3dp6
    PDB 3dpe-3e1w
    PDB 3e1z-3ebh
    PDB 3ebi-3epk
    PDB 3epl-3f28
    PDB 3f2b-3fhe
    PDB 3fhp-3ful
    PDB 3fum-3g9y
    PDB 3ga3-3gpu
    PDB 3gpx-3h2w
    PDB 3h3e-3hfy
    PDB 3hgz-3hsn
    PDB 3hso-3i8v
    PDB 3i9b-3ij6
    PDB 3ijf-3ixe
    PDB 3iz0-3k34
    PDB 3k35-3kiy
    PDB 3kj1-3kvt
    PDB 3kwa-3lat
    PDB 3lcn-3lrr
    PDB 3ls1-3m1n
    PDB 3m1v-3mek
    PDB 3men-3mru
    PDB 3ms0-3n63
    PDB 3n64-3nin
    PDB 3nis-3ny2
    PDB 3ny3-3ohc
    PDB 3ohd-3oyl
    PDB 3oym-3pih
    PDB 3pki-3r0d
    PDB 3rj7-3t74
    PDB 3t87-3u9g
    PDB 3ua7-3v24
    PDB 3v25-4agl
    PDB 4agm-4dih
    PDB 4dii-4efs
    PDB 4eg2-4fc8
    PDB 4fgm-6tli
    PDB 6tmn-9nse

Chemical Properties of Zinc






Zinc tarnishes rapidly in air. It burns to the oxide when heated, and zinc wool burns with a brilliant flame when lighted with a Bunsen burner - forming a coherent mass of oxide.

In dry oxygen oxidation virtually ceases below 150° C. when the surface film has formed. As the temperature rises above this, moist oxygen begins to act more vigorously than dry. Ozone attacks the metal somewhat more actively than oxygen.

Basic carbonates are formed by atmospheric action upon zinc, and hydrogen peroxide can be detected during the rusting.

Steam acts readily on the metal at a red heat, but the reaction

ZnO+H2OZnO+H2

is reversible. Potable waters dissolve zinc, and distilled or rain water dissolves it more readily than harder water, though purified water has been said to have no action on the metal.

Ground waters may take up 5 parts of zinc per million when they pass through galvanised iron pipes.

According to Davies, all waters attack zinc when air is present. Coating the zinc, he adds, does not stop the action, and zinc is found in the viscera of people who have drunk water containing zinc compounds. Moderate hardness in the water favours the action, he also says, extreme hardness does not prevent it, and rain-water has the least action.

The corrosion of zinc by acidic reagents is greater when the metal contains lead, cadmium, or iron than in the refined product. Minute traces of arsenic, antimony, copper, or tin also favour corrosion.

Aqueous halogen acids dissolve zinc to the halide with evolution of hydrogen. The rate of dissolution in hydrochloric acid depends upon the condition of the metal, also upon the impurities present, and the action is very slow if the metal is pure. Dry hydrogen chloride has a solvent action in the following solvents: chloroform, ethyl chloride, amyl alcohol, methyl alcohol, ethyl alcohol, acetone, ethyl ether, and benzene.

Zn+2HCl.200H2O = ZnCl2.400H2O+H2+36.820 Cal.

if the hydrogen is dry. The corresponding figure for moist hydrogen at the same temperature, 20° C., is 36.070 Cal.

Zinc reacts with dilute aqueous sulphuric acid to form hydrogen and zinc sulphate, but if the metal is very pure there is scarcely any action. There is probably no action at all if both acid and metal are exceedingly pure, and the rate of solution varies with the condition of the zinc and the impurities present. Solution proceeds more slowly at first, and this preliminary "induction period" is probably due to a layer of hydrogen bubbles that prevents contact between the metal and the acid. Rise of temperature increases the rate of solution, and its effect increases with the acid concentration, though it has no appreciable effect when the acid is very dilute. Amalgamation protects zinc from attack by acids, because the discharge potential of hydrogen on mercury exceeds the potential of zinc.

Small quantities of sulphur dioxide and hydrogen sulphide are often produced during the action of dilute sulphuric acid on ordinary zinc, though they are not produced if the acid and metal are nearly pure. Sulphur dioxide is the chief gaseous product when the sulphuric acid is concentrated, but hydrogen sulphide is also produced at higher temperatures, and both compounds are formed when the temperature is fairly high (160° C.).

When zinc is heated in a stream of sulphur dioxide some sulphide seems to be formed. When aqueous sulphurous acid acts on zinc the sulphite and salts of other sulphur acids are produced in the solution. If the action occurs at 200° C. in sealed tubes, amorphous zinc sulphide, sulphur, and zinc sulphate result. Zinc hydrosulphite or hyposulphite is formed if dry sulphur dioxide is passed through a suspension of zinc in absolute alcohol, and, according to Bernsthen, the reaction

Zn+2SO2 = ZnS2O4

first occurs when aqueous sulphurous acid acts upon zinc. Secondary reactions then occur. According to Schutzenberger, zinc sulphite and zinc hydrosulphite are the primary products, and no hydrogen is produced.

According to Fordos and Gelis, zinc sulphite and hydrogen are produced first. Then the nascent hydrogen reduces some sulphurous acid to hydrogen sulphide. This may precipitate part of the sulphite (this occurs to a considerable extent with cadmium) as sulphide, and it also interacts with sulphur dioxide to form sulphur. The sulphur finally reacts with some zinc sulphite to produce zinc thiosulphate. Since zinc sulphide reacts with excess of sulphurous acid according to the equation

2ZnS+3SO2 = 2ZnS2O3+S,

as Henderson and Weiser point out, Fordos and Gelis obtained a solution of zinc sulphite and thiosulphate when they acted upon the metal with an excess of sulphurous acid. They noted that the decomposition

2ZnS2O3 = ZnS+ZnS3O6

readily occurs.

The reaction between zinc and sulphurous acid may apparently vary with the conditions, but the formation of various thionic acids has usually been explained by the primary formation of zinc sulphite and nascent hydrogen. Zinc sulphide has a tendency to precipitate from solutions resulting from the action of sulphurous acid on zinc from the decomposition of zinc thiosulphate, etc.

According to Schweitzer, zinc sulphite and thiosulphate are first formed, and the liquid also ultimately contains sulphur, zinc sulphide, and trithionate. Nascent hydrogen, he adds, is not produced, and is not responsible for any reactions.

According to Acworth and Armstrong, nitric oxide, nitrous oxide, and nitrogen are always evolved by the action of nitric acid on zinc. Montemartini says that hyponitrous acid, nitric oxide, nitrous oxide, nitrogen, and ammonia are formed at a low temperature with a large excess of acid. Nitrous acid is also formed if the solution does not contain more than 30 per cent, of acid, and nitrogen peroxide if it does. A maximum of ammonia is produced with acid of concentration 40.45 at a temperature of 3°-8° C., a maximum of nitrous oxide at a concentration of 40 and a minimum at 80, a maximum of nitrogen peroxide at a concentration of 80, which then remains constant, and nitrogen is never formed in more than very small quantities. Hydroxylamine is said to be produced during the action of nitric acid on zinc, and to be easily observable if sulphuric or another acid is present. Bijlert detected no hydroxylamine when N/20 to N/10 nitric acid acted upon zinc - ammonia was formed. Nitrous acid has been said to be the primary product of the reaction.

Zinc dissolves slowly in caustic alkalies, forming hydrogen and zincates.

Zinc apparently forms no compound with hydrogen, though the spectrum of an arc between zinc poles in hydrogen has been said to indicate zinc hydride, and the existence of zinc hydride has been affirmed. The metal, however, is apt to occlude hydrogen, and zinc dust has been said to contain thirty-nine times its volume of this gas.

It decomposes nitric oxide slowly but completely at 600° C., and unites directly with most of the negative elements.

Zinc displaces less electropositive metals from solutions of their salts, and a zinc-copper couple, prepared by depositing copper on zinc, decomposes water at ordinary temperatures. This evolution of hydrogen accounts, it seems probable, for the production of this gas when zinc displaces copper and other metals from their solutions. The zinc-copper couple is an effective reducing agent, and will decompose water even at 2° C. A properly prepared couple is suitable for estimating nitrogen (by reducing it to ammonia) in water.

There is a period of induction when metals are replaced in solutions of their salts by zinc, and they may be precipitated partly in the form of hydroxide, nickel, and cobalt, for example. If asbestos is wrapped round a zinc rod that is dipped in a solution of lead acetate, or copper sulphate, or antimony chloride and tartaric acid, a spongy mass of metal settles out on the asbestos. A black deposit of antimony also drops to the bottom of the vessel, that explodes when heated (explosive antimony).

Zinc and copper have been said to be reciprocally replaceable by one another to some extent under appropriate conditions, and a solution of an iron salt was said to be produced by acting on the solution of a normal zinc salt with powdered iron.

Hydrogen is evolved when magnesium is immersed in a solution of zinc chloride, and zinc containing some hydroxide is precipitated.15 Magnesium will only precipitate 50 per cent, of the zinc from a solution of zinc sulphate, and the precipitated zinc contains some oxides of magnesium and zinc. Aluminium reacts with solutions of zinc salts.


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