Tambayoyi Misali Game da Maganin Buffer
Maganin buffer, wanda aka fi sani da buffer, mafita ce da ke kiyaye pH ɗinta koda lokacin da aka ƙara ƙaramin adadin acid mai ƙarfi ko tushe. Wannan ikon yana sa mafita ta buffer ta zama mahimmanci a aikace-aikacen sinadarai daban-daban, halittu, har ma da masana'antu. A cikin wannan labarin, za mu bincika wasu misalai kuma mu tattauna mafita ta buffer.
Fahimtar Maganin Buffer
Maganin buffer gabaɗaya yana ƙunshe da cakuda mai rauni acid da tushen haɗinsa ko tushe mai rauni da acid ɗin haɗinsa. Idan aka ƙara acid ko tushe a cikin waɗannan mafita, sakamakon da ya haifar yana taimakawa wajen kiyaye pH na maganin a cikin takamaiman iyaka. A cikin wannan mahallin, pH ma'auni ne na acidity ko alkalinity na maganin.
Aiki da Muhimmancin Maganin Buffer
Buffers suna da muhimmiyar rawa a fannoni daban-daban:
1. Biochemistry: Yawancin halayen enzymatic da physiological suna faruwa a wani takamaiman pH, don haka mafita na buffer suna taimakawa wajen kiyaye yanayi mafi kyau.
2. Masana'antu: A masana'antun abinci da magunguna, ingantaccen kula da pH yana da mahimmanci ga ingancin samfura da aminci.
3. Gwaje-gwajen Sinadarai: A dakin gwaje-gwaje, ana amfani da mafita na buffer don sarrafa pH yayin halayen sinadarai.
Yadda Maganin Buffer ke Aiki
Maganin buffer yana aiki ne bisa ƙa'idar daidaito. Ga maganin da ya ƙunshi acid mai rauni \(HA \) da gishirin tushensa mai haɗuwa \(A^- \), ƙara ƙaramin adadin acid ko tushe zai haifar da canjin yanayi ba tare da babban canji a cikin yawan ions na \(H^+ \) ba.
Tambayoyi da Tattaunawa Samfura
Domin ƙarin fahimtar hakan, bari mu yi nazari kan wasu tambayoyi da tattaunawa da suka shafi mafita ta hanyar amfani da buffer.
Tambaya ta 1: Lissafin pH na Maganin Buffer na Acid
Tambaya:
Ana yin maganin buffer ta hanyar haɗa 0,1 mol na acetic acid (CH₃COOH) da 0,1 mol na sodium acetate (CH₃COONa) a cikin lita 1 na maganin. Matsakaicin rabuwar acetic acid (\( K_a \)) shine \( 1,8 \sau 10^{-5} \). Lissafa pH na maganin.
Tattaunawa:
Wannan maganin buffer ya ƙunshi acid mai rauni (CH₃COOH) da tushen haɗin gwiwa (CH₃COO⁻). Za mu iya amfani da lissafin Henderson-Hasselbalch don ƙididdige pH na maganin buffer:
\[ \text{pH} = \text{p}K_a + \log \left( \frac{[A^-]}{[HA]} \right) \]
Ina:
\[ \text{p}K_a = -\log (K_a) \]
\[ \text{p}K_a = -\log (1,8 \sau 10^{-5}) \]
\[ \text{p}K_a \approx 4,74 \]
Tunda yawan \( [A^-] \) da \( [HA] \) iri ɗaya ne (0,1 M):
\[ \text{pH} = 4,74 + \log \left( \frac{[0,1]}{[0,1]} \right) \]
\[ \text{pH} = 4,74 + \log(1) \]
\[ \rubutu{pH} = 4,74 \]
Don haka, pH na maganin buffer shine 4,74.
Tambaya ta 2: Ƙara Maganin Acid a cikin Buffer
Tambaya:
Menene canjin pH idan aka ƙara 0,01 mol na HCl a cikin lita 1 na maganin buffer daga Tambaya ta 1?
Tattaunawa:
Ƙarin HCl zai ƙara yawan \( H^+ \ ) a cikin maganin. Amsar da ke faruwa ita ce:
\[ \text{H}^+ + \text{CH}_3\text{COO}^- \rightarrow \text{CH}_3\text{COOH} \]
Muna buƙatar ƙididdige adadin mole na \( H^+ \) da kuma yadda yake shafar yawan \( \text{CH}_3\text{COOH} \) da \( \text{CH}_3\text{COO}^- \).
Da farko:
\[ [\text{CH}_3\text{COO}^-] = 0,1 \, \text{mol} \]
\[ [\text{CH}_3\text{COOH}] = 0,1 \, \text{mol} \]
Bayan ƙara 0,01 mol na HCl:
\[ [\text{CH}_3\text{COO}^-] = 0,1 – 0,01 = 0,09 \, \text{mol} \]
\[ [\text{CH}_3\text{COOH}] = 0,1 + 0,01 = 0,11 \, \text{mol} \]
Yi amfani da lissafin Henderson-Hasselbalch don ƙididdige sabon pH:
\[ \text{pH} = \text{p}K_a + \log \left( \frac{[A^-]}{[HA]} \right) \]
\[ \text{pH} = 4,74 + \log \left( \frac{0,09}{0,11} \right) \]
\[ \text{pH} = 4,74 + \log(0,818) \]
\[ \text{pH} = 4,74 + (-0,088) \]
\[ \rubutu{pH} = 4,65 \]
Don haka, pH na maganin buffer bayan ƙara HCl yana canzawa daga 4,74 zuwa 4,65.
Tambaya ta 3: Ƙara Tushe zuwa Maganin Buffer
Tambaya:
Menene canjin pH idan aka ƙara 0,01 mol na NaOH a cikin lita 1 na maganin buffer daga Tambaya ta 1?
Tattaunawa:
Ƙara NaOH zai rage yawan H⁺ a cikin maganin ta hanyar OH⁻ daga NaOH. Halayen da ke faruwa:
\[ \text{OH}^- + \text{CH}_3\text{COOH} \rightarrow \text{CH}_3\text{COO}^- + \text{H}_2\text{O} \]
Da farko:
\[ [\text{CH}_3\text{COOH}] = 0,1 \, \text{mol} \]
\[ [\text{CH}_3\text{COO}^-] = 0,1 \, \text{mol} \]
Bayan ƙara 0,01 mol na NaOH:
\[ [\text{CH}_3\text{COOH}] = 0,1 – 0,01 = 0,09 \, \text{mol} \]
\[ [\text{CH}_3\text{COO}^-] = 0,1 + 0,01 = 0,11 \, \text{mol} \]
Yi amfani da lissafin Henderson-Hasselbalch don ƙididdige sabon pH:
\[ \text{pH} = \text{p}K_a + \log \left( \frac{[A^-]}{[HA]} \right) \]
\[ \text{pH} = 4,74 + \log \left( \frac{0,11}{0,09} \right) \]
\[ \text{pH} = 4,74 + \log(1,222) \]
\[ \text{pH} = 4,74 + 0,087 \]
\[ \rubutu{pH} = 4,83 \]
Don haka, pH na maganin buffer bayan ƙara NaOH yana canzawa daga 4,74 zuwa 4,83.
Tambaya ta 4: Tantance Tsarin Buffer tare da takamaiman pH
Tambaya:
Domin yin lita 1 na maganin buffer tare da pH 5,0 ta amfani da acetic acid (CH₃COOH) da sodium acetate (CH₃COONa), adadin moles na kowane sashi ake buƙata? \(K_a \) na acetic acid shine \( 1,8 \sau 10^{-5} \).
Tattaunawa:
Yi amfani da lissafin Henderson-Hasselbalch:
\[ \text{pH} = \text{p}K_a + \log \left( \frac{[A^-]}{[HA]} \right) \]
Da farko, lissafta pKₐ:
\[ \text{p}K_a = -\log (1,8 \sau 10^{-5}) \]
\[ \text{p}K_a \approx 4,74 \]
Sannan, shigar da ƙimar pH da ake so:
\[ 5,0 = 4,74 + \log \left( \frac{[A^-]}{[HA]} \right) \]
\[ 0,26 = \log \left( \frac{[A^-]}{[HA]} \right) \]
Amfani da kaddarorin logarithms:
\[ \frac{[A^-]}{[HA]} = 10^{0,26} \]
\[ \frac{[A^-]}{[HA]} \kimanin 1,82 \]
Wannan yana nufin cewa ga kowace mole 1 na CH₃COOH, ana buƙatar moles 1,82 na CH₃COONa. Don wannan rabo a cikin lita 1:
Misali, bari mu ce CH₃COOH = x mol, don haka CH₃COONa = 1,82x mol. Jimlar girman shine (x + 1.82x) = 2,82x mol, tunda muna yin lita 1 na buffer, to:
\[ x + 1.82x = 1 \]
\[ 2.82x = 1 \]
\[ x = \frac{1}{2.82} \kimanin 0.355 \]
Don haka, abun da ake buƙata:
– CH₃COOH: 0,355 mol
- CH₃COONa: 1,82 0,355 ≈ 0,646 mol
Don haka muna buƙatar mol 0,355 na acetic acid da mol 0,646 na sodium acetate don yin lita 1 na maganin buffer tare da pH 5,0.
Wannan labarin ya gabatar da misalai daban-daban na matsaloli da suka shafi mafita ta hanyar amfani da hanyar sadarwa ...
