Ma’ruza: Eritmаlаr. Foiz, Molyar va Normal konsentratsiya eritmalarini tayyorlash. Fiksanal eritmalar tayyorlash. Reja

Molyar kontsentratsiya yoki molyarlik. Bunda eritma kontsentratsiyasi erigan moddaning 1 litr eritmadagi mollar soni bilan ifodalanadi.

The value of Ksp indicates the solubility of an ionic compound—the smaller the value, the less soluble the compound in water. However, in using Ksp values to compare solubilities, you should choose compounds that have similar formulas, such as AgCl and ZnS, or CaF2 and Fe(OH)2. There are two other quantities that express a substance’s solubility: molar solubility, which is the number of moles of solute in 1 L of a saturated solution (moles per liter), and solubility, which is the number of grams of solute in 1 L of a saturated solution (grams per liter). Note that all these expressions refer to the concentration of saturated solutions at some given temperature (usually 25C).

Figure 17.9 shows the relationships among solubility, molar solubility, and Ksp.

Agar 1 l eritmada 1 mol erigan modda bo’lsa, bunday eritma kontsentratsiyasi 1 molyar bo’ladi va M bilan belgilanadi. Agar 1l eritmada 0,1 mol eruvchi modda bo’lsa, uning kontsentratsiyasi detsimolyar eritma deyiladi. (0,1 M ). Yuqoridagi ta‘rifga binoan

C_M = ;

3. Normal eritma deb 1 litr eritmada erigan moddaning ekvivalentlar soniga aytiladi. Bunday eritmalar normal eritmalar deb ataladi. Ular C_N yoki n harfi bilan ifodalanadi. Chunonchi, 2 n H₂SO₄ eritmasi deganda bir litr eritmada 2 ekvivalent sulfat kislota erigan deb tushunish kerak.

O’zaro reaksiyaga kirishayotgan eritmalarning normal konsentratsiyalari o’zaro teng bo’lsa, bu eritmalar qoldiqsiz reaksiyaga kirishadi. Bunday eritma-larning qoldiqsiz reaksiyaga kirishadigan hajmlari ularning normalliklariga teskari proporsionaldir:

V₁ : V₂ = N₂ : N₁

Bu nisbatdagi V₁ – birinchi eritmaning hajmi, V₂ – ikkinchi eritmaning xajmi, N₁ – birinchi eritmaning normalligi, N₂ – ikkinchi eritmaning normalligi.

Bu tenglama asosida reaksiya uchun kerak bo’ladigan eritmalarning hajmigina emas, balki reaksiya uchun sarf bo’lgan eritmalarning konsentratsiyasini ham hisoblab topish mumkin.

1 - m i s o l. 20 ml 0,15 n li sulfat kislota eritmasini neytrallash uchun 0,1 n li litiy gidroksid eritmasidan necha ml kerak?

E ch i sh. 0,1 n li NaOH eritmasidan necha ml kerak bo’lishini quyidagi tenglama bilan topamiz:

Bundan

2 – m i s o l. 25 ml xlorid kislota eritmasini neyirallash uchun 0,1 n li KOH eritmasidan 40 ml sarf bo’ldi. Kislotaning normal konsentratsiyasini toping?

E ch i sh. Xlorid kislotaning normal konsentratsiyasini quyidagicha topamiz: