Gịnị bụ dissociation nke mmiri?

A akpan akpan bụrụ na nke dissociation (ire ere usoro ibu ahụ nke okwu - molekụla ion ma ọ bụ radicals - ka obere ahụ) bụ electrolytic dissociation, adịru na-anọpụ iche molekul mara electrolyte na ngwọta (site mmetụta nke ụmụ irighiri nke pola mgbaze) gbasaa n'ime ebubo ahụ: cations na anions. Nke a na-akọwa na ike nke electrolyte ngwọta na-eduzi ọkụ eletrik.

Ọ kpebiri ịkọrọ niile electrolytes abụọ dị iche iche: na-adịghị ike ma dị ike. Mmiri na-ezo aka na-adịghị ike electrolytes, na dissociation nke mmiri e ji obere ego nke dissociated ụmụ irighiri ihe, ebe ọ bụ na ha zuru ezu na-eguzogide ọgwụ na ọ nweghị dissociate n'ime ion. Pure (mma n'anya) mmiri agụghị oké enịmde eletriki ugbu a. Nke a bụ n'ihi na chemical ọdịdị nke molekul onwe ya, mgbe ghaghị ekewasị hydrogen atọm na-ẹkenam n'ime ihe electronic envelopu dịtụ obere oxygen atọm nke a na-ezighị ezi-ekewasị.

The ike na adịghị ike nke electrolyte e ji a ogo dissociation (gosiri site α, a buru ibu na-mgbe mgbe n'ụzọ dị ka a% nke 0 100, ma ọ bụ na ụmụ irighiri ihe nke a unit si 0 ka 1) - ike disintegrate n'ime ion, i.e. ruru nke ọnụ ọgụgụ nke gbajiri ahụ n'etiti ndị ahụ daa. Bekee ndị dị otú ahụ dị ka acid na isi salts site n'oru nke pola mmiri ụmụ irighiri dissociate n'ime ion kpamkpam. The dissociation nke mmiri ụmụ irighiri H2O sochiri disintegration n'ime a proton H + ma ọ bụ hydroxyl otu OH-. Ọ bụrụ na dissociation nke electrolyte ugbu n'ụdị akụkụ: M = K ++ A-, mgbe ahụ, mmiri dissociation nwere ike kwupụtara na akụkụ: OH N2O↔N ++, na akụkụ nke gbakọrọ ogo mmiri dissociation nwere ike na-anọchi anya abụọ forms (site n'ihi ịta nke protons ma ọ bụ hydroxyl iche iche n'ihi ịta): α = [H +] / [H2O] ma ọ bụ α = [OH -] / [H2O]. Ebe ọ bụ na ego α na-emetụta ọ bụghị naanị site na chemical ọdịdị nke compound, ma ihe ngwọta ịta ma ọ bụ okpomọkụ, ọ bụ omenala na-ekwu okwu banyere ihe ndị yiri (chepụtara echepụta) ogo dissociation.

Propensity ụmụ irighiri na-adịghị ike electrolytes, gụnyere mmiri, dissociate n'ime ion n'ụzọ dị ukwuu ji a dissociation mgbe nile (akpan akpan bụrụ na ịha mgbe nile), nke nwere ike họpụtara dị ka KD. Gbakọọ a bara uru, iwu nke uka edinam, nke na-esetịpụrụ ndị ruru n'etiti ọha mmadụ enwetara site na-amalite ihe. An electrolytic dissociation nke mmiri - a decomposition amalite mmiri ụmụ irighiri n'ime hydrogen protons na hydroxyl otu, Otú ọ dị na dissociation mgbe nile na-kwupụtara site akụkụ: KD = [H +] • [OH -] / [H2O]. Nke a mmiri buru ibu bụ mgbe nile na-adabere naanị na okpomọkụ, na okpomọkụ nke 25C, KD = 1,86 • 10-16.

Ịmata ezengwenri uka nke mmiri (18 grams / ahumachi), na eleghara ịta nke dissociated ụmụ irighiri na-ewere uka nke 1 dm3 mmiri kwa 1000 g, nwere ike gbakọọ ịta nke undissociated ụmụ irighiri na 1 dm3 mmiri [H2O] = 1000 / 18.0153 = 55.51 mol / dm3. Mgbe ahụ, site na akụkụ nke dissociation mgbe nile pụrụ ịchọta ngwaahịa ịta nke protons na hydroxyl iche iche: [H +] • [OH -] = 1,86 • 10-16 • 55,51 = 1 • 10-14. Mgbe adịrị ndị square mgbọrọgwụ nke na n'ihi uru nwetara ịta nke protons (hydrogen ion), nke na-ekpebi acidity nke ngwọta na ịta nke hydroxyl iche iche hà: [H +] = [OH -] = 1 • 10-7.

Ma na ọdịdị dị otú ahụ na-adị ọcha mmiri adịghị adị n'ihi na nke ọnụnọ nime ya nke etisasịwo, haruru ma ọ bụ mmiri ofufe site ọzọ bekee (N'eziokwu mmiri - a ngwọta dị iche iche electrolytes), nke mere na ịta nke hydrogen na 25 ° C ịta nke protons ma ọ bụ hydroxyl iche iche dị iche iche site ụkpụrụ nke 1 • 10-7. Nke ahụ bụ, acidity nke mmiri ruru ka omume nke ọ bụghị nanị na a usoro dị ka dissociation mmiri. The hydrogen index bụ ọjọọ logarithm nke hydrogen ion ịta (onye Onyenwe anyị +), ọ na ẹkenam imata na acidity ma ọ bụ alkalinity nke mmiri na okenye agbanwe agbanwe, dị ka nọmba na-adịghị mma ike iji ike. N'ihi na dị ọcha mmiri onye Onyenwe anyị + 7, ma dị ka ndammana dị ọcha mmiri bụghị, na dissociation nke mmiri aga tinyere ida nke ọzọ etisasịwo electrolytes, onye Onyenwe anyị + bara uru pụrụ ịdị ala karịa ma ọ bụ ukwuu karịa 7, i.e. maka mmiri, fọrọ ≠ onye Onyenwe anyị + 7.