25- lab.mashg’uloti. 12-guruh elementlari. Rux, kadmiy va simob birikmalari. Laboratoriya ishining maqsadi: Talabalarni 12-gurux elementlari, rux, guruhchasi elementlari va ularning birikmalari bilan tanishtirish.
Rux guruhchasi elementlari va ularning birikmalari bo’yicha tajribalar:
Zarur asbob va reaktivlar: gorelka, shtativ probirkalar bilan. Chinni hovoncha dastasi bilan. Rux qirindisi yoki bo‘lakchalari. Natriy (metall) . Simob (metall) .
Eritmalar: sulfat kislota (kons. va 2 n) , xlorid kislota (kons. va 2 n) , nitrat kislota (kons. va 2 n) , 2n CdSO4 ; 2 n NaOH; 2 n ZnSO4; 2 n Na2S; 2 n; NH4OH NH4Cl (to‘yingan) ; 1 n simob (I) nitrat; 1 n simob (II) nitrat.
1-tajriba. Kadmiyni kadmiy tuzlari eritmasidan rux ta’sirida siqib chiqarish Probirkaga 5-6 tomchi 2 n kadmiy sulfat eritmasidan solib, unga kichikroq bir bo‘lakcha rux metallidan soling va chayqating. Vaqt o‘tishi bilan rux ustida kadmiyning hosil
bo‘lishini kuzatib, reaksiya tenglamasini molekulyar va ionli shaklda yozing.
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Xulosa._______________________________________________________________________________________________________________________________________________________________________________________________________________
2-tajriba. Ruxning kislota va ishqorlarda erishi. a) alohida probirkalarga 5-7 tomchidan suyultirilgan (2 n) va konsentrlangan ( =1,84 g/sm3) sulfat kislotalaridan solib, unga rux qirindisi (yoki bir bo‘lak rux) tashlang. Sovuqda reaksiya ketmasa, probirkalarni ohista isiting. Probirkalarda ajralib chiqayotgan gazlarga e’tibor berib, reaksiya tenglamalarini yozing. Oksidlovchi va qaytaruvcxilarni
aniqlang;
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b)ikkita probirka olib, biriga 2 n xlorid kislota, ikkinchisiga 2 n natriy gidroksid eritmalaridan 5-7 tomchidan soling. Har ikkala probirkaga rux qirindisidan (rux bo‘lakchasi) ozgina qo‘shing. Reaksiya tenglamalarini yozib, hosil bo‘lgan
tuzlar nomini ayting.
_____________________________________________________________________________________________________________________________________________________________________________________________________________________ Xulosa._______________________________________________________________________________________________________________________________________________________________________________________________________________3- tajriba. Rux va kadmiy gidroksidlarning olinishi va ularning xossalari a) probirkaga 8-10 tomchi 2 n rux sulfat eritmasidan solib, unga oq, iviq cho‘kma hosil bo‘lguncha tomchilatib o‘yuvchi natriy eritmasidan qo‘shing (probirkani chayqatib turing. Cho‘kma erib ketmasin) . Hosil bo‘lgan cho‘kmani ikki probirkaga teng bo‘lib, birinchisiga suyultirilgan sulfat, ikkinchisiga esa o‘yuvchi ishqor eritmasidan ko‘proq qo‘shing. Har ikkala probirkada cho‘kmaning erib ketishini kuzatib, reaksiya tenglamalarini molekulyar va ionli shaklda yozing. Zn(OH)2 qanday xususiyatga ega? ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________b) a banddagi tajribani probirkaga 2 n kadmiy sulfat solib takrorlang. Nimalarni kuzatamiz? Cd(OH)2 qanday xususiyatga ega?
___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Xulosa._______________________________________________________________________________________________________________________________________________________________________________________________________________4- tajriba. Rux va kadmiy sulfidlarning olinishi, ularning xossalari Ikkita probirka olib, birinchisiga 4-5 tomchi rux sulfat eritmasidan, ikkinchisiga shuncha kadmiy sulfat eritmasidan tomizing. Har bir probirkaga cho‘kma hosil bo‘lguncha natriy sulfide eritmasidan tomchilatib qo‘shing. Hosil bo‘lgan cho‘kmalarning rangiga e’tibor berib, reaksiya tenglamalarini molekulyar va ionli shaklda yozing. Har ikkala probirkadagi cho‘kmalar ustidagi suvni to‘king va ularga bir xil hajmda suyiltirilgan xlorid kislota qo‘shib, rux va kadmiy sulfidlarning eruvchanligini kuzatgan holda reaksiya tenglamalarini yozing:
( Kek ZnS= 8*10 -26 ; Kek CdS =1.10 -29 )
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Xulosa._______________________________________________________________________________________________________________________________________________________________________________________________________________
