Ihe Nlereanya nke Ajụjụ Mkparịta ụka nke Mmiri Nnu
Mmiri nnu bụ ihe na-eme na kemịkalụ nke gụnyere mmeghachi omume nke nnu na mmiri, na-emepụta acid ma ọ bụ ntọala dị ka ihe na-esote. Usoro a na-abụkarị isiokwu dị mkpa na nkuzi kemistri n'ihi na nghọta nke mmiri nnu nwere ike inye nghọta bụ isi banyere njirimara nke ngwọta ma nyere aka n'ịchọpụta pH nke ngwọta. N'isiokwu a, anyị ga-atụle ọtụtụ nsogbu atụ na ngwọta ha metụtara mmiri nnu.
Echiche Ndị Dị Mkpa nke Mmiri Nnu
Mmiri nnu na-apụta mgbe nnu gbawara n'ime mmiri, ion ya na-emekwaghachi omume na molekul mmiri iji mepụta asịd ma ọ bụ ntọala. Ọ bụghị nnu niile ga-agbanwe mmiri n'ime mmiri; ụfọdụ na-anọpụ iche, nke pụtara na ha anaghị agbanwe pH nke ngwọta ahụ. Agbanyeghị, ụfọdụ nnu nwere ike ịmepụta ngwọta acidic ma ọ bụ isi, dabere na isi iyi nke asịd na ntọala nke mepụtara nnu ahụ.
Iji ghọta usoro a, ọ dị mkpa ịmara na:
– Nnu nke asịd siri ike na ntọala siri ike (dịka NaCl) anaghị amịpụta mmiri mmiri, ihe ngwọta ahụ na-anọpụ iche.
– Nnu nke asịd ndị na-adịghị ike na ntọala siri ike (dịka CH3COONa) na-emepụtakarị ngwọta ndị bụ isi.
– Nnu nke asịd siri ike na ntọala ndị na-adịghị ike (dịka NH4Cl) na-emepụtakarị mmiri acid.
– Nnu nke asịd ndị na-adịghị ike na ntọala ndị na-adịghị ike nwere ike imeghachi omume na mmiri ma chọpụta pH ikpeazụ dabere na ike nke asịd na ntọala ahụ.
Ajụjụ na Mkparịta ụka Ihe Nlereanya
Ajụjụ nke 1: Mmiri nke Potassium Acetate (CH3COOK)
Ajụjụ:
Mmiri potassium acetate (CH3COOK) ọ bụ acidic, ihe dị mfe, ka ọ bụ ihe na-anọpụ iche? Dee mmeghachi omume hydrolysis nke na-eme ma chọpụta pH nke mmiri ahụ.
Azịza:
Potassium acetate (CH3COOK) bụ nnu nke asịd na-adịghị ike (acetic acid, CH3COOH) na ntọala siri ike (potassium hydroxide, KOH). Site na nke a, anyị nwere ike ikwubi na ngwọta CH3COOK nwere ike ịbụ ihe dị mfe n'ihi na ion acetate (CH3COO⁻) nwere ike ịgbaze na mmiri.
Mmeghachi omume bụ dịka ndị a:
\[ CH_3COO^- + H_2O \rightleftharpoons CH_3COOH + OH^- \]
Aịọn Acetate (CH3COO⁻) na-anabata protons (H⁺) site na mmiri (H2O) iji mepụta acetic acid (CH3COOH) na ion hydroxide (OH⁻). Ọnụnọ nke ion hydroxide (OH⁻) na mmiri na-eme ka ọ bụrụ ihe dị mfe.
Iji chọpụta pH, anyị chọrọ njupụta nke ion OH⁻. Dịka ọmụmaatụ, anyị nwere ngwọta 0,1 M CH3COOK na ionization constant nke acetic acid (Ka) bụ 1,8 × 10⁻⁵.
Nzọụkwụ ndị e mere bụ:
1. Iji ntọala na-agbanwe agbanwe (Kb) maka ion CH3COO⁻:
\[ K_b = \frac{K_w}{K_a} = \frac{10^{-14}}{1,8 \ugboro 10^{-5}} = 5,56 \ugboro 10^{-10} \]
2. Kewaa ion CH3COO⁻ na mmiri:
\[ K_b = \frac{[CH_3COOH][OH^-]}{[CH_3COO^-]} \]
Ka ọkwa nkewapụ bụrụ 'x':
\[ 5,56 \ugboro 10^{-10} = \frac{x^2}{0,1-x} \]
Ọ bụrụ na anyị eleghara obere \(x\) dị na denominator anya, anyị nwere ike ime ka ọ dị mfe:
\[ x^2 \ihe dị ka 5,56 \u003 10^{-11} \Akara aka nri x = \sqrt{5,56 \u003 10^{-11}} = 7,45 \u003 10^{-6} \]
Ntinye uche OH⁻:
\[ [OH^-] = 7,45 \ugboro 10^{-6} \]
pOH nke ngwọta ahụ:
\[ pOH = -\log [OH^-] = -\log (7,45 \ugboro 10^{-6}) \ihe dị ka 5,13 \]
Iji njikọ dị n'etiti pH na pOH:
[pH = 14 – pOH = 14 – 5,13 = 8,87 \]
Ya mere, ngwọta CH3COOK bụ nke dị mfe ma nwee pH ihe dịka 8,87.
Ajụjụ nke 2: Mmiri nke Ammonium Chloride (NH4Cl)
Ajụjụ:
Mmiri ammonium chloride (NH4Cl) ọ bụ acidic, ihe dị mfe, ma ọ bụ ihe na-anọpụ iche? Dee mmeghachi omume hydrolysis nke na-eme ma chọpụta pH nke mmiri ahụ.
Azịza:
Ammonium chloride (NH4Cl) bụ nnu nke asịd siri ike (HCl) na ntọala adịghị ike (NH3). Site na nke a, anyị nwere ike ikwubi na ngwọta ahụ bụ asịd n'ihi na ammonium ion (NH4⁺) nwere ike ịgbaze n'ime mmiri.
Mmeghachi omume bụ dịka ndị a:
\[ NH_4^+ + H_2O \rightleftharpoons NH_3 + H_3O^+ \]
Iọn Ammonium (NH4⁺) na-enye protons (H⁺) na molekul mmiri (H2O) iji mepụta ammonia (NH3) na ion hydronium (H3O⁺). Ọnụnọ nke ion hydronium (H3O⁺) na ngwọta a na-eme ka ngwọta ahụ bụrụ acidic.
Dịka ọmụmaatụ, anyị nwere ihe ngwọta 0,1 M NH4Cl. Ihe na-agbanwe agbanwe ionization ntọala (Kb) maka NH3 bụ 1,8 × 10⁻⁵.
Nzọụkwụ ndị e mere bụ:
1. Iji ihe na-agbanwe agbanwe (Ka) maka ion NH4⁺:
\[ K_a = \frac{K_w}{K_b} = \frac{10^{-14}}{1,8 \ugboro 10^{-5}} = 5,56 \ugboro 10^{-10} \]
2. Kewaa ion NH4⁺ na mmiri:
\[ K_a = \ frac {[NH_3][H_3O^+]}{[NH_4^+]} \]
Ka ọkwa nkewapụ bụrụ 'x':
\[ 5,56 \ugboro 10^{-10} = \frac{x^2}{0,1-x} \]
Ọ bụrụ na anyị eleghara obere \(x\) dị na denominator anya, anyị nwere ike ime ka ọ dị mfe:
\[ x^2 \ihe dị ka 5,56 \u003 10^{-11} \Akara aka nri x = \sqrt{5,56 \u003 10^{-11}} = 7,45 \u003 10^{-6} \]
Ntinye H3O⁺:
\[ [H_3O^+] = 7,45 \ugboro 10^{-6} \]
pH nke ngwọta ahụ:
\[ pH = -\log [H_3O^+] = -\log (7,45 \ugboro 10^{-6}) \ihe dị ka 5,13 \]
Ya mere, ngwọta NH4Cl bụ acidic nwere pH ihe dịka 5,13.
N'ihe atụ abụọ dị n'elu, anyị na-ahụ ka ịchọpụta ụdị hydrolysis nwere ike isi nyere aka chọpụta ụdị ngwọta. Site n'itinye ionization balance constant (Ka ma ọ bụ Kb) na echiche ole na ole dị mfe, anyị nwere ike idozi nsogbu ndị a n'ụzọ dị mfe.
Mkparịta ụka a gbasara nsogbu nnu hydrolysis abụghị naanị na ọ na-azụ nkà nyocha na mgbakọ na mwepụ kamakwa ọ na-eme ka nghọta nke echiche ndị bụ isi nke kemistri ngwọta dịkwuo omimi. Ịghọta otu ion sitere na mmalite dị iche iche si enye protons ma ọ bụ ndị na-anabata ihe na molekul mmiri, na otu nke a si emetụta pH nke ngwọta, dị mkpa iji mụta ọtụtụ isiokwu dị elu na kemistri.
