Glukozaning Mis (II)-gidroksid bilan reaksiyasi.
I.Kerakli jixoz va reaktivlar: probirka, shtativ, spirt lampasi, natriy gidroksid, glukoza, Mis (II)-gidroksid,kraxmal , yod, kaliy yodid
II.Ishning borishi:
1-tajriba.Probirkaga 2-3 ml glukoza eritmasidan va shu miqdorda suyultirilgan Natriy gidroksid eritmasidan soling (NaOH dan ortiqcha miqdorda olinishi kerak). So‘ng bir necha tomchi Mis (II)-gidroksid eritmasidan qo‘shing. Probirkada hosil bo‘lgan eritmani kuzating.
Mustaqil xulosalar uchun topshiriqlar. 1. Zangori rangli eritma nima? Ushbu tajriba nimani isbotlaydi?
2. Nima uchun probirkadagi eritma qizdirilganda avval sariq so‘ngra qizil
cho‘kma hosil bo‘ladi?
3. Tegishli reaksiya tenglamalarini yozing.
2-tajriba. Kraxmal kleysterini tayyorlash va kraxmalning yod bilan reaksiyasi.
Probirkaga 4-5 ml suv soling, ozgina kraxmal qo‘shing va aralashmani
chayqating. Hosil bo‘lgan suspenziyani probirkadagi qaynab turgan suvga eritmani
doimo chayqatib turib oz-ozdan qo‘shing.
Hosil bo‘lgan kleysterni sovuq suv bilan suyultiring (1:20) va ikkita probirkaga
3-5 ml dan soling. Bitta probirkaga yodning spirtdagi eritmasidan ozroq,
ikkinchisiga esa kaliy yodid eritmasidan qo‘shing.
Mustaqil xulosalar uchun topshiriq.
1.Nima uchun ko‘k rang faqat birinchi probirkada paydo bo‘ldi?
2.Tegishli reaksiyalarning tenglamalarini yozing
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