Mohlala oa Lipotso tsa Puisano tsa Brønsted-Lowry Acid-Based
Li-acid le metheo ke mehopolo ea bohlokoa k'hemistri e ntlafalitsoeng le ho hloekisoa ke bo-rasaense ba bangata ho theosa le lilemo. E 'ngoe ea likhopolo-taba tse tsebahalang haholo ke khopolo-taba ea Brønsted-Lowry, e hlahisitsoeng ke Johannes Nicolaus Brønsted le Thomas Martin Lowry ka 1923. Khopolo-taba ena e fana ka pono e batsi ea hore na li-acid le metheo li sebelisana joang liketsong tsa lik'hemik'hale. Sehloohong sena, re tla tšohla mehlala e 'maloa ea mathata a amanang le khopolo ea Brønsted-Lowry ea li-acid le metheo le mokhoa oa ho li rarolla.
Mehopolo ea Motheo ea Brønsted-Lowry Acids le Bases
Ho ya ka kgopolo ya Brønsted-Lowry, asiti ke ntho e ka fanang ka proton (H+), ha motheo e le ntho e ka amohelang proton. Dikarabelong tsa dikhemikhale, di-acid le di-base di sebelisana ka mokgwa wa phetisetso ya proton, moo motsoako o mong o sebetsang jwalo ka asiti ka ho lokolla proton, mme motsoako o mong o sebetsa jwalo ka motheo ka ho amohela proton.
Mehlala ea Likarabelo tsa Motheo oa Asiti
Mohlala oa karabelo e bonolo pakeng tsa asiti le motheo ho ea ka khopolo-taba ea Brønsted-Lowry ke karabelo pakeng tsa koporo(II) sulfate (H2SO4) le sodium hydroxide (NaOH):
\[ \text{H}_2\text{SO}_4 + \text{NaOH} \rightarrow \text{NaHSO}_4 + \text{H}_2\text{O} \]
Karabelong ena, asiti ea sulfuric (H2SO4) e sebetsa e le asiti ea Brønsted-Lowry hobane e fana ka proton (H+) ho NaOH ea motheo, e amohelang proton.
Lipotso le Lipuisano tsa Mehlala
Potso ea 1: Ho Khetholla Li-acid le Metheo
Potso:
Hlalosa li-acid le metheo ea Brønsted-Lowry liketsong tse latelang:
\[ \text{NH}_3 + \text{H}_2\text{O} \rightarrow \text{NH}_4^+ + \text{OH}^- \]
Puisano:
Karabelong ena, ammonia (NH3) le metsi (H2O) ke di-reactant, ha di-ion tsa ammonium (NH4+) le di-ion tsa hydroxide (OH-) e le dihlahiswa. A re boneng hore na ke efe e sebetsang jwalo ka asiti le hore na ke efe e sebetsang jwalo ka motheo.
– NH3 e sebetsa e le motheo hobane e amohela liprothone (H+) ho tloha ho H2O ho theha NH4+.
– H2O e sebetsa e le asiti hobane e fana ka proton (H+) ho NH3 ho theha OH-.
Kahoo, karabelong ena:
– NH3 ke setsi sa Brønsted-Lowry.
– H2O ke asiti ya Brønsted-Lowry.
Potso ea 2: Ho Ngola Likarabelo tsa Kopano
Potso:
Ngola lipara tsa conjugate acid-base bakeng sa likarabo tse latelang:
\[ \text{HCl} + \text{H}_2\text{O} \rightarrow \text{H}_3\text{O}^+ + \text{Cl}^- \]
Puisano:
Karabelong ena, HCl e sebetsa e le asiti ea Brønsted-Lowry ka ho fana ka proton (H+) ho H2O. Metsi (H2O) a amohela proton mme a sebetsa e le motheo oa Brønsted-Lowry. Kamora ho lahleheloa ke proton, HCl e fetoha Cl-, 'me H2O, kamora ho fumana proton, e fetoha H3O+.
– Asiti (HCl) le motheo oa eona oa conjugate (Cl-)
– Motheo (H2O) le asiti ea eona e kopaneng (H3O+)
Ka hona, para ea conjugate acid-base karabelong ena ke:
– HCl/Cl-
– H2O / H3O+
Potso ea 3: Ho bala pH ea Tharollo ea Asiti e Fokolang
Potso:
Bala pH ea tharollo ea 0.1 M ea asiti ea acetic (CH3COOH) haeba ho tsejoa hore kamehla ea karohano ea asiti (Ka) ke \(1.8 \makhetlo a 10^{-5}\).
Puisano:
Asiti ea acetic ke asiti e fokolang, 'me ka metsing e ionis hanyane feela ho latela equation e latelang:
\[ \text{CH}_3\text{COOH} \rightleftharpoons \text{CH}_3\text{COO}^- + \text{H}^+ \]
Mehato ea ho bala pH ke ena:
1. Beha polelo ea tekano u sebelisa mahloriso a pele le phetoho ea mahloriso:
\[ \text{Ka} = \frac{[\text{CH}_3\text{COO}^-][\text{H}^+]}{[\text{CH}_3\text{COOH}]} \]
2. Kenya boleng bo tsejoang sebakeng sa \([H^+]\):
\[ 1.8 \makgetlo a 10^{-5} = \frac{x^2}{0.1 – x} \]
Kaha \(x\) e nyane haholo ha e bapiswa le 0.1, re ka hakanya \(0.1 - x \hoo e ka bang 0.1\):
\[ 1.8 \makgetlo a 10^{-5} = \frac{x^2}{0.1} \]
\[ x^2 = 1.8 \makgetlo a 10^{-6} \]
\[ x = \sqrt{1.8 \makgetlo a 10^{-6}} \]
\[ x \hoo e ka bang 1.34 \makgetlo a 10^{-3} \]
3. Bala pH:
\[ \text{pH} = -\log[\text{H}^+] \]
\[ \text{pH} = -\log(1.34 \makgetlo a 10^{-3}) \]
\[ \text{pH} \hoo e ka bang 2.87 \]
Kahoo, pH ea tharollo ea asiti ea acetic ea 0.1 M e ka ba 2.87.
Potso ea 4: Ho Khetholla Litharollo tsa Amphiprotic
Potso:
Hlalosa tharollo ea amphiprotic karabelong e latelang 'me u hlalose lebaka:
\[ \text{HCO}_3^- + \text{H}_2\text{O} \rightleftharpoons \text{H}_2\text{CO}_3 + \text{OH}^- \]
Puisano:
Tharollo ea amphiprotic ke tharollo e ka sebetsang e le asiti kapa motheo, ho latela maemo a karabelo. Mohlala oa karabelo o kaholimo:
– \(\text{HCO}_3^-\) e sebetsa e le motheo ha e amohela proton ho tloha ho \(\text{H}_2\text{O}\), e hlahisa \(\text{H}_2\text{CO}_3\).
– \(\text{HCO}_3^-\) e ka boela ea sebetsa e le asiti tlas'a maemo a mang, ea lokolla proton 'me ea hlahisa \(\text{CO}_3^{2-}\).
Sena se bontša hore ion ea \(\text{HCO}_3^-\) ke amphiprotic. E ka sebetsa e le asiti (proton donor) le motheo (proton acceptor), ho latela ntho e 'ngoe eo e arabelang ka eona.
Ka mathata ana a mehlala, re ka utloisisa hamolemo kamoo khopolo-taba ea motheo oa asiti ea Brønsted-Lowry e sebelisoang kateng ho sekaseka le ho bolela esale pele likamano tsa lik'hemik'hale. Kutloisiso e tiileng ea khopolo-taba ena ke motheo oa lits'ebetso tse ngata k'hemistri, biochemistry le mahlale a mang.
