Nitric acid

Muaj zog monobasic acid, uas yog nyob rau hauv tus qauv tej yam kev mob tsis muaj kob kua uas puv daj thaum lub sij hawm cia tej zaum yuav nyob rau hauv ib tug khoom hauv lub xeev, yus muaj los ntawm ob tug crystalline modifications (monoclinic los yog orthorhombic lattice) nyob rau hauv kub hauv qab no Rho tawm 41,6 ° C. Qhov no tshuaj nrog cov tshuaj mis - HNO3 - nitric acid yog hu ua. Nws muaj ib tug hniav puas loj 63,0 g / tias, thaum nws ceev sau raws nkaus Ii 1,51 g / cm³. acid reflux kub yog 82,6 ° C, yog nrog los ntawm decomposition ntawm lub (ib nrab): 4HNO3 → 2H2O + 4NO2 + O2. acid tov nrog ib tug loj feem ntawm qhov yooj yim tshuaj ntawm 68% boils ntawm ib tug kub ntawm 121 ° C. Lub refractive index ntawm cov ntshiab tshuaj sau raws nkaus Ii 1.397. Acid yuav tov nrog dej nyob rau hauv tej piv thiab, ua ib tug muaj zog ntsha, yuav luag tag tawg ua me me mus rau hauv ions H + thiab NO3-. Khoom daim ntawv - trihydrate thiab monohydrate muaj cov mis: HNO3 • 3H2O thiab HNO3 • H2O feem.

Nitric acid - xeb active, tshuaj lom tshuaj, thiab ib tug muaj zog oxidizing neeg sawv cev. Los ntawm cov Nrab Hnub nyoog paub hais tias lub npe, raws li "muaj zog dej» (Aqua fortis). Alchemists uas pheej nrhiav acid nyob rau hauv lub xyoo pua 13th, muab lub npe kom paub tseeb tias nws extraordinary zog (corroded tag nrho co tsuas yog kub), surpassing ib lab lub sij hawm lub hwj chim ntawm acetic acid, uas nyob rau hauv cov hnub suav hais tias lub feem ntau kom nquag plias. Tab sis txawm tom qab peb centuries nws tau raug pom tias corrode, txawm kub yuav ua tau ib tug sib tov ntawm acids xws li nitric thiab hydrochloric ntawm ib tug ntim ratio ntawm 1: 3, uas rau no yog vim li cas hu ua "aqua regia". Cov tsos ntawm ib tug daj xim thaum lub sij hawm cia yog vim tsub zuj zuj ntawm nitrogen oxides nyob rau hauv nws. Qhov acid nrog ib tug concentration ntau 68%, thiab thaum twg cov ntsiab lus ntawm lub hauv paus cov ntaub ntawv uas tshaj 89% nws yog hu ua "fuming".

Cov tshuaj thaj chaw ntawm nitric acid, paub qhov txawv nws los ntawm qhov nta sulfuric los yog hydrochloric acid uas HNO3 muaj zog oxidant yog li ntawd yeej tsis tso hydrogen nyob rau hauv tshua nrog hlau. Vim lub oxidative zog, nws kuj reacts nrog ntau uas tsis yog-hlau. Thiab nyob rau hauv ob leeg yog ib txwm tsim nitrogen dioxide NO2. Nyob rau hauv redox tshua, ib tug nitrogen rov qab tshwm sim los ua degrees: HNO3, NO2, N2O3, TSIS MUAJ, N2O, N2, NH3, uas yog txiav txim los ntawm lub acid concentration thiab kev ua si ntawm cov hlau. Cov molecules ntawm lub tebchaw tsim muaj nitrogen nyob rau hauv oxidation xeev +5, +4, +3, +2, +1, 0, +3, ntsig txog. Piv txwv li, tooj liab yog oxidized nrog concentrated acid rau tooj liab nitrate (II): Cu + 4HNO3 → 2NO2 + Cu (NO3) 2 + 2H2O, thiab phosphorus - mus metaphosphoric acid: P + 5HNO3 → 5NO2 + HPO3 + 2H2O.

Txwv tsis pub ua num ua ke nrog nta nitric acid nonmetals. Nyob rau hauv qhov piv txwv ntawm cov tshuaj tiv thaiv uas lub phosphorus: 3P + 5HNO3 + 2H2O → 3H3PO4 + 5NO pom hais tias cov nitrogen yog txo mus rau lub divalent lub xeev. Cov no ib tug nitric oxide thiab phosphorus yog oxidized rau acid phosphate. Concentrated nitric acid nyob rau hauv admixture nrog hydrochloric acid yaj kub: Au + 4HCl + HNO3 → TSIS + H [AuCl4] + 2H2O thiab platinum: 3Pt + 18HCl + 4HNO3 → 4NO + 3H2 [PtCl6] + 8H2O. Nyob rau hauv cov tshuaj, chiv, hydrochloric acid yog oxidized nrog nitric tshuaj tso tawm, thiab ces tsim ib tug complex hlau chlorides.

Nitric acid yog ua lag luam tau nyob rau hauv peb lub ntsiab txoj kev:

1. Keeb kwm - reacting lub ntsev nrog sulfuric acid: H2SO4 + NaNO3 → HNO3 + NaHSO4. Yav tas los, nws yog tus tsuas yog txoj kev uas yuav, tab sis nrog lub advent ntawm lwm yam technologies, nws yog tam sim no siv nyob rau hauv txoj kev kuaj yuav tsim fuming acid.
2. Ob - nws yog ib txoj kev arc. Thaum huab cua tshaj ib tug hluav taws xob arc nrog ib tug kub ntawm 3000 mus 3500 ° C, ib feem ntawm nitrogen nyob rau hauv cov huab cua reacts nrog cov pa, txoj kev ua nitrogen monoxide: N2 + O2 → 2NO, uas tom qab txias yog oxidized rau nitrogen dioxide (tsis hnov mob hauv ib tug kub monoxide nrog rau oxygen) : O2 + 2NO → 2NO2. Ces, suab, tag nrho nitrogen dioxide, nyob rau ntawm ib tshaj ntawm cov pa, yaj nyob rau hauv dej: 2H2O + 4NO2 + O2 → 4HNO3.
3. Peb - qhov no yog ib qho ammonia txoj kev. Ammonia yog oxidized nyob rau platinum catalyst rau nitrogen monoxide: 4NH3 + 5O2 → 4NO + 6H2O. Cov uas ua cov pa roj nitrous gases yog txias, thiab cov tsim nitrogen dioxide, uas yog absorbed los ntawm cov dej. Los ntawm cov qauv no, cov acid muaj ib tug concentration ntawm 60 mus rau 62%.

Nitric acid yog dav siv nyob rau hauv kev lag luam los tsim cov tshuaj, dyes, foob pob, nitric chiv thiab nitric acid ntsev. Nyob rau hauv tas li ntawd, nws yog siv rau cov xaus ntawm hlau (e.g., tooj liab, hmoov txhuas, silver) uas tsis hnov mob nrog rau lwm cov acids. Cov hniav nyiaj hniav kub siv rau qhov kev txiav txim ntawm kub nyob rau hauv lub hlau (qhov no yog qhov tseem ceeb txoj kev).