Kimyo bakalavr) 2021-2022 o’quv yili I semester uchun II kurs (III semestr) namangan – 2021

Taxminiy 0,1 N NaOH eritmasini oksalat kislotaning birlamchi standart eritmasi bo'yicha standartlash.

Byuretka ishqorning tayyorlangan eritmasi bilan, Mоg pipetkasida tayyorlangan oksalat kislota eritmasi bilan 2-3 martadan chayib tashlanadi. So'ngra shu pipetka yordamida konussimon kolbaga oksalat kislota eritmasidan alikvot qism (20-25 ml) solinib, uning ustiga fenolftalein eritmasidan 2-3 tomchi tomiziladi. Konussimon kolbadagi oksalat kislotaning standart eritmasi byuretkadagi NaOH eritmasi bilan kolbani uzluksiz aralashtirib turgan holda, 30 sek mobaynida yo'qolmaydigan och qizg'ish rang hosil bo'lguncha titrlanadi. Qayta titrlashlarda qo'shilayotgan NaOH eritmasi indikator rangi o'zgarishiga 0,5 ml chamasi qolganda asta-sekin tomchilatib qo'shiladi. Titrlash kamida uch marta takrorlanadi.

NaOH eritmasining normalligi quyidagi formula yordamida hisoblanadi:

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