Cov khoom no yog cylindrical, muaj ib qho nyuaj thiab elastic npliag capsule muaj li ntawm lub hau thiab lub cev uas tuaj yeem haum thiab kaw ua ke. Cov tshuaj ntsiav yuav tsum du, sib xws hauv cov xim, nrog rau kev txiav huv, tsis muaj deformation, thiab tsis muaj ntxhiab tsw. Nws muaj nyob rau hauv peb hom: pob tshab (tsis muaj seem muaj tus neeg sawv cev opaque), ib nrab - pob tshab (tsuas yog ib ntu muaj tus neeg sawv cev opaque), thiab opaque (ob ntu muaj tus neeg sawv cev opaque).
Noj 0.25 g ntawm cov khoom no, ntxiv 50 ml ntawm dej, tshav kub kom yaj, txias, co zoo, noj 5ml ntawm cov tshuaj, ntxiv ob peb tee ntawm poov tshuaj dichromate test tov - dilute hydrochloric acid (4: 1), thiab txiv kab ntxwv - daj flocculent precipitate yuav raug tsim; noj 1ml ntawm cov tshuaj raws li kev txheeb xyuas (1), ntxiv 50ml dej, co zoo, ntxiv ob peb tee ntawm tannic acid test tov, thiab turbidity yuav tshwm sim; noj li 0.3g ntawm cov khoom no, muab tso rau hauv ib lub raj kuaj, ntxiv me ntsis sodium txiv qaub, cua sov, thiab cov roj uas tsim tau tuaj yeem tig daj litmus daim ntawv xiav.
