Misali na Tambayoyin Tattaunawa na Brønsted-Lowry Acid-Base
Acids da tushe muhimman ra'ayoyi ne a fannin ilmin sunadarai waɗanda masana kimiyya da yawa suka haɓaka kuma suka inganta tsawon shekaru. Ɗaya daga cikin shahararrun ra'ayoyin shine ka'idar Brønsted-Lowry, wadda Johannes Nicolaus Brønsted da Thomas Martin Lowry suka gabatar a shekarar 1923. Wannan ka'idar tana ba da faffadan ra'ayi game da yadda acid da tushe ke hulɗa a cikin halayen sinadarai. A cikin wannan labarin, za mu tattauna misalai da yawa na matsaloli da suka shafi ra'ayin Brønsted-Lowry na acid da tushe da kuma yadda za a magance su.
Ka'idojin Asali na Brønsted-Lowry Acids da Bases
A cewar ka'idar Brønsted-Lowry, acid abu ne da zai iya bayar da proton (H+), yayin da tushe abu ne da zai iya karɓar proton. A cikin halayen sinadarai, acid da tushe suna hulɗa ta hanyar tsarin canja wurin proton, inda wani mahaɗin yana aiki azaman acid ta hanyar sakin proton, ɗayan mahaɗin kuma yana aiki azaman tushe ta hanyar karɓar proton.
Misalan Amsoshin Tushen Acid
Misali na wani abu mai sauƙi tsakanin acid da tushe bisa ga ka'idar Brønsted-Lowry shine amsawar da ke tsakanin jan ƙarfe (II) sulfate (H2SO4) da sodium hydroxide (NaOH):
\[ \text{H}_2\text{SO}_4 + \text{NaOH} \rightarrow \text{NaHSO}_4 + \text{H}_2\text{O} \]
A cikin wannan amsawar, sinadarin sulfuric acid (H2SO4) yana aiki a matsayin sinadarin Brønsted-Lowry saboda yana bayar da proton (H+) ga tushen NaOH, wanda ke karɓar proton.
Tambayoyi da Tattaunawar Samfura
Tambaya ta 1: Gano Acid da Tushe
Tambaya:
Gano sinadaran Brønsted-Lowry da kuma tushensu a cikin waɗannan halayen:
\[ \text{NH}_3 + \text{H}_2\text{O} \rightarrow \text{NH}_4^+ + \text{OH}^- \]
Tattaunawa:
A cikin wannan amsawar, ammonia (NH3) da ruwa (H2O) sune sinadaran amsawar, yayin da ammonium ions (NH4+) da hydroxide ions (OH-) sune samfuran. Bari mu ga wanne ke aiki a matsayin acid kuma wanne ke aiki a matsayin tushe.
– NH3 yana aiki a matsayin tushe saboda yana karɓar protons (H+) daga H2O don samar da NH4+.
– H2O yana aiki a matsayin acid saboda yana ba da proton (H+) ga NH3 don samar da OH-.
Don haka, a cikin wannan martanin:
– NH3 tushe ne na Brønsted-Lowry.
– H2O wani sinadari ne na Brønsted-Lowry acid.
Tambaya ta 2: Martanin Rubutu game da Haɗawa
Tambaya:
Rubuta nau'ikan haɗin acid-base don halayen masu zuwa:
\[ \text{HCl} + \text{H}_2\text{O} \rightarrow \text{H}_3\text{O}^+ + \text{Cl}^- \]
Tattaunawa:
A cikin wannan amsawar, HCl yana aiki a matsayin Brønsted-Lowry acid ta hanyar ba da proton (H+) ga H2O. Ruwa (H2O) yana karɓar proton kuma yana aiki a matsayin tushen Brønsted-Lowry. Bayan rasa proton, HCl yana juyawa zuwa Cl-, kuma H2O, bayan samun proton, yana juyawa zuwa H3O+.
- Acid (HCl) da tushen haɗin gwiwa (Cl-)
– Tushe (H2O) da sinadarin haɗin gwiwa (H3O+)
Saboda haka, haɗin acid-base biyu a cikin wannan amsawar shine:
– HCl / Cl-
– H2O / H3O+
Tambaya ta 3: Lissafin pH na Maganin Rauni na Acid
Tambaya:
Lissafa pH na maganin acetic acid mai girman 0.1 M (CH3COOH) idan an san cewa ma'aunin rabuwar acid (Ka) shine \(1.8 \sau 10^{-5}\).
Tattaunawa:
Acetic acid wani acid ne mai rauni, kuma a cikin ruwa yana yin ionizes ne kawai a cikin wani ɓangare bisa ga lissafin da ke ƙasa:
\[ \text{CH}_3\text{COOH} \rightleftharpoons \text{CH}_3\text{COO}^- + \text{H}^+ \]
Matakan da ake bi don ƙididdige pH sune kamar haka:
1. Saita yanayin daidaitawa ta amfani da farkon yawan abu da kuma canjin yawan abu:
\[ \text{Ka} = \frac{[\text{CH}_3\text{COO}^-][\text{H}^+]}{[\text{CH}_3\text{COOH}]} \]
2. Sauya dabi'un da aka sani kuma a warware su don \([H^+]\):
\[ sau 1.8 10^{-5} = \frac{x^2}{0.1 – x} \]
Tunda \(x\) ƙarami ne idan aka kwatanta da 0.1, za mu iya kimanta \(0.1 – x \approx 0.1\):
\[ sau 1.8 10^{-5} = \frac{x^2}{0.1} \]
\[ x^2 = 1.8 \sau 10^{-6} \]
\[ x = \sqrt{1.8 \sau 10^{-6}} \]
\[ x \kimanin 1.34 \sau 10^{-3} \]
3. Lissafa pH:
\[ \text{pH} = -\log[\text{H}^+] \]
\[ \text{pH} = -\log(1.34 \sau 10^{-3}) \]
\[ \text{pH} \approx 2.87 \]
Don haka, pH na maganin acid na M 0.1 shine kusan 2.87.
Tambaya ta 4: Gano Maganin Amphiprotic
Tambaya:
Gano maganin amphiprotic a cikin wannan amsawar kuma bayyana dalilin:
\[ \text{HCO}_3^- + \text{H}_2\text{O} \rightleftharpoons \text{H}_2\text{CO}_3 + \text{OH}^- \]
Tattaunawa:
Maganin amphiprotic shine maganin da zai iya aiki a matsayin acid ko tushe, ya danganta da yanayin amsawar. A cikin misalin amsawar da ke sama:
– \(\text{HCO}_3^-\) yana aiki a matsayin tushe lokacin da ya karɓi proton daga \(\text{H}_2\text{O}\), yana samar da \(\text{H}_2\text{CO}_3\).
– \(\text{HCO}_3^-\) kuma zai iya aiki a matsayin acid a ƙarƙashin wasu yanayi, yana sakin proton kuma yana samar da \(\text{CO}_3^{2-}\).
Wannan yana nuna cewa ion ɗin \(\text{HCO}_3^-\) amphiprotic ne. Yana iya aiki a matsayin acid (proton donor) da kuma tushe (proton acceptor), ya danganta da sauran sinadarin da yake amsawa da shi.
Da waɗannan matsalolin misali, za mu iya fahimtar yadda ake amfani da ka'idar Brønsted-Lowry acid-base don nazarin da kuma hasashen hulɗar sinadarai. Fahimtar wannan ka'idar ita ce ginshiƙin aikace-aikace da yawa a fannin sinadarai, biochemistry, da sauran kimiyya.
