Tambayoyi Misali Game da Ƙarfin da pH na Acid da Bases
Ƙarfin tushen acid da pH muhimman batutuwa ne a fannin sinadarai, musamman a fannin acid da tushe. A cikin wannan labarin, za mu tattauna yadda za a tantance ƙarfin acid da tushe da kuma ƙididdige pH na mafita ta amfani da misalai da dama na matsaloli.
Gabatarwa ga Acid da Bases
Asamu
Asid wani sinadari ne da ke iya fitar da ions na hydrogen (H⁺) idan ya narke a cikin ruwa. Dangane da ikonsu na sakin ions na H⁺, an rarraba acid zuwa nau'i biyu:
1. Acid mai ƙarfi: Acid wanda ke raba 100% a cikin ruwan, yana fitar da ions na H⁺ gaba ɗaya. Misalan: Acid na Hydrochloric (HCl), acid na sulfuric (H₂SO₄), nitric acid (HNO₃).
2. Rauni acid: Wani acid ne wanda ke rabuwa da wani ɓangare kawai a cikin ruwan da ke cikinsa, wasu daga cikin ƙwayoyin suna fitar da ions na H⁺. Misalan: Acetic acid (CH₃COOH), carbonic acid (H₂CO₃), hydrocyanic acid (HCN).
tushe
Tushe wani sinadari ne da zai iya fitar da ions na hydroxide (OH⁻) idan ya narke a cikin ruwa. Dangane da ikonsu na sakin ions na OH⁻, an kuma rarraba tushen zuwa nau'i biyu:
1. Tushe mai ƙarfi: Tushe wanda ke raba 100% a cikin ruwan, yana fitar da ions OH⁻ gaba ɗaya. Misalan: Sodium hydroxide (NaOH), potassium hydroxide (KOH).
2. Tushe mara ƙarfi: Tushe ne wanda ke rabuwa kaɗan a cikin ruwan da ke cikinsa, wasu daga cikin ƙwayoyin ne kawai ke fitar da ions na OH⁻. Misalan: Ammonia (NH₃), magnesium hydroxide (Mg(OH)₂).
Tsarin pH
pH ma'auni ne na acidity ko alkalinity na wani bayani. An bayyana shi a matsayin logarithm mara kyau na yawan sinadarin hydrogen ion (H⁺):
\[ \text{pH} = – \log [H⁺] \]
Don mafita na asali, ana amfani da pOH, wanda aka bayyana a matsayin logarithm mara kyau na yawan ion hydroxide (OH⁻):
\[ \text{pOH} = – \log [OH⁻] \]
Alaƙa tsakanin pH da pOH shine:
\[ \text{pH} + \text{pOH} = 14 \]
Ana kiran pH 7 a matsayin tsaka-tsaki, pH ƙasa da 7 a matsayin acidic, kuma pH sama da 7 a matsayin alkaline.
Tambayoyi da Tattaunawa Samfura
Misali Tambaya ta 1: Lissafin pH na Acid Mai Ƙarfi
Tambaya: Kayyade pH na maganin HCl na 0,01 M.
Tattaunawa: HCl wani sinadari ne mai ƙarfi wanda zai rabu gaba ɗaya zuwa ions na H⁺ da Cl⁻. Tunda yana da molarity na 1:1 tsakanin HCl da H⁺, yawan H⁺ shine 0,01 M.
\[ \text{pH} = – \log [H⁺] \]
\[ \text{pH} = – \log (0,01) \]
\[ \rubutu{pH} = 2 \]
Don haka, pH na maganin HCl na 0,01 M shine 2.
Misali Tambaya ta 2: Lissafin pH na Acid Mai Rauni
Tambaya: Kayyade pH na maganin 0,1 M CH₃COOH (acetic acid) idan \( K_a \) na CH₃COOH shine \( sau 1,8 10^{-5} \).
Tattaunawa: Raunanan acid ba sa rabuwa gaba ɗaya, don haka muna amfani da ma'aunin rabuwar acid (\( K_a \) ) don tantance yawan H⁺. Ga CH₃COOH, lissafin rabuwa shine:
\[ \text{CH₃ COOH} \rightleftharpoons \text{H⁺} + \text{CH₃ COO⁻} \]
Daga ƙa'idar maganin buffer, mun ɗauka cewa \( x \) shine yawan ions na H⁺ da aka samar:
\[ K_a = \frac{ [H⁺][CH₃ COO⁻] }{ [CH₃ COOH] } \]
\[ sau 1,8 10^{-5} = \frac{ (x)(x) }{ 0,1 – x } \]
Tunda \( x \) ƙarami ne idan aka kwatanta da 0,1 M, za mu iya yin watsi da x a cikin ma'aunin rabo:
\[ sau 1,8 sau 10^{-5} \approx \frac{ x^2 }{ 0,1 } \]
\[ x^2 \kimanin 1,8 \sau 10^{-6} \]
\[ x \kimanin \sqrt{ 1,8 \sau 10^{-6} } \]
\[ x \kimanin 1,34 \sau 10^{-3} \]
Don haka, yawan H⁺ shine ( sau 1,34 10^{-3} \):
\[ \text{pH} = – \log [H⁺] \]
\[ \text{pH} = – \log (1,34 \sau 10^{-3}) \]
\[ \text{pH} \approx 2,87 \]
Don haka, pH na maganin 0,1 M CH₃COOH kusan 2,87 ne.
Misali Tambaya ta 3: Lissafin pH na Tushe Mai Ƙarfi
Tambaya: Kayyade pH na maganin NaOH na 0,01 M.
Tattaunawa: NaOH tushe ne mai ƙarfi wanda zai rabu gaba ɗaya cikin ions na Na⁺ da OH⁻. Tunda yana da molarity na 1:1 tsakanin NaOH da OH⁻, yawan OH⁻ shine 0,01 M.
\[ \text{pOH} = – \log [OH⁻] \]
\[ \text{pOH} = – \log (0,01) \]
\[ \rubutu{pOH} = 2 \]
Amfani da alaƙar \( \text{pH} + \text{pOH} = 14 \):
\[ \text{pH} = 14 – \text{pOH} \]
\[ \text{pH} = 14 – 2 \]
\[ \rubutu{pH} = 12 \]
Don haka, pH na maganin NaOH na 0,01 M shine 12.
Misali Tambaya ta 4: Lissafin pH na Tushen Rauni
Tambaya: Kayyade pH na maganin 0,1 M NH₃ idan \( K_b \) na NH₃ shine \( sau 1,8 10^{-5} \).
Tattaunawa: Tushen da ba su da ƙarfi ba sa rabuwa gaba ɗaya, don haka muna amfani da ma'aunin rabuwar tushe (\( K_b \) ) don tantance yawan OH⁻. Ga NH₃, lissafin rabuwar shine:
\[ \text{NH₃ + H₂O} \rightleftharpoons \text{NH₄⁺ + OH⁻} \]
Ta hanyar amfani da hanya ɗaya da ta shafi raunin acid, muna ɗauka cewa yawan ions na OH⁻ da aka samar shine:
\[ K_b = \frac{ [NH₄⁺][OH⁻] }{ [NH₃] } \]
\[ 1,8 \ lokuta 10 ^ {-5} = \ frac { (y) (y) }{ 0,1 - y } \]
Idan aka ɗauka cewa \( y \) ƙarami ne, lissafin zai zama:
\[ sau 1,8 sau 10^{-5} \approx \frac{ y^2 }{ 0,1 } \]
\[ y^2 \kimanin sau 1,8 10^{-6} \]
\[ y \kimanin \sqrt{ 1,8 \sau 10^{-6} } \]
\[ y \kimanin 1,34 \sau 10^{-3} \]
Yawan OH⁻ shine \( sau 1,34 10^{-3} \):
\[ \text{pOH} = – \log [OH⁻] \]
\[ \text{pOH} = – \log (1,34 \sau 10^{-3}) \]
\[ \text{pOH} \approx 2,87 \]
Amfani da alaƙar \( \text{pH} + \text{pOH} = 14 \):
\[ \text{pH} = 14 – 2,87 \]
\[ \text{pH} \approx 11,13 \]
Don haka, pH na maganin 0,1 M NH₃ shine kusan 11,13.
Kammalawa
Tabbatar da pH na mafita da fahimtar ƙarfin acid da tushe muhimmin tushe ne a fannin sinadarai. Acid mai ƙarfi da tushe suna rabuwa gaba ɗaya a cikin mafita, yayin da acid mai rauni da tushe ke rabuwa kaɗan kawai. Amfani da \(K_a \) da \(K_b \) yana sauƙaƙa ƙididdige pH na acid mai rauni da tushe. Waɗannan ƙwarewa suna da mahimmanci don amfani a fannoni daban-daban, gami da masana'antu, magunguna, da kimiyyar muhalli. Ta hanyar fahimtar ra'ayoyi da nazarin misalai, za mu iya magance matsalolin da suka shafi pH da ƙarfin acid a cikin rayuwar yau da kullun cikin sauƙi.
