Mehlala ea Lipotso Tse Buisanang ka pH ea Li-Acid tse Matla le Metheo e Matla
pH, kapa bokgoni ba haeterojene, ke tekanyo ya asiti kapa alkalinity ya tharollo. Sekala sa pH se tloha ho 0 ho isa ho 14, mme dipalo tse ka tlase ho 7 di bontsha tharollo ya asiti, dipalo tse ka hodimo ho 7 di bontsha tharollo ya motheo, mme 7 di bontsha tharollo e sa nke lehlakore. Sehloohong sena, re tla buisana ka mehlala e mmalwa ya mathata mabapi le pH ya di-acid tse matla le metheo e matla, hammoho le ditharollo tsa tsona.
Pendahuluan
Mehopolo ea Motheo ea pH
pH ke tekanyo e sebediswang ho fumana hore na asiti kapa alkalinity ya tharollo e itshetlehile hodima mahloriso a di-ion tsa haeterojene (H+). Foromo ya motheo ya ho bala pH ke:
\[ \text{pH} = -\log{[H^+]} \]
Moo [H+] e leng mahloriso a li-ion tsa haedrojene ho mol/L.
Ka lehlakoreng le leng, bakeng sa ditharollo tsa motheo (metheo e matla), re ka bala pOH pele ebe re e fetolela ho pH re sebedisa foromo e latelang:
\[ \text{pOH} = -\log{[OH^-]} \]
\[ \mongolo{pH} = 14 – \mongolo{pOH} \]
Asiti e Matla khahlanong le Asiti e Fokolang
Asiti e matla ke asiti e ionisang ka botlalo ka hara tharollo ya metsi. Sena se bolela hore mahloriso a di-ion tsa H+ ka hara tharollo a lekana le mahloriso a asiti ka boyona. Mehlala ya di-acid tse matla ke HCl (hydrochloric acid), HNO3 (nitric acid), le H2SO4 (sulfuric acid).
Ka lehlakoreng le leng, li-acid tse fokolang ha li ionise ka botlalo tharollong, kahoo lipalo tsa tsona tsa pH li rarahane haholo 'me li hloka mohopolo oa acidity constant (Ka).
Motheo o Matla khahlanong le Motheo o Fokolang
Joalo ka li-acid tse matla, metheo e matla le eona e ionisa ka botlalo ka har'a tharollo ea metsi. Mehlala ea metheo e matla ke NaOH (sodium hydroxide) le KOH (potassium hydroxide).
Metheo e fokolang e na le ionized ka karolo e itseng feela mme e hloka mohopolo oa basicity constant (Kb) ho bala pH.
Lipotso tsa Mehlala le Puisano
Mohlala oa Potso ea 1: Asiti e Matla
> Bala pH ea tharollo ea 0.01 M HCl.
Puisano:
Kaha HCl ke asiti e matla, e tla ionisa ka botlalo ka tharollong.
\[ \text{HCl} \rightarrow \text{H}^+ + \text{Cl}^- \]
Khatello ea li-ion tsa H+ ka har'a tharollo e tla tšoana le khatello ea HCl e fanoeng, e leng 0.01 M.
\[ [H^+] = 0.01 \, \mongolo{M} \]
Ho sebelisa foromo ea pH:
\[ \text{pH} = -\log{[H^+]} = -\log{0.01} = -\log{10^{-2}} = 2 \]
Kahoo, pH ea tharollo ea 0.01 M HCl ke 2.
Mohlala oa Potso ea 2: Metheo e Matla
> Bala pH ea tharollo ea NaOH ea 0.001 M.
Puisano:
NaOH ke motheo o matla 'me e tla ionisa ka botlalo tharollong.
\[ \text{NaOH} \rightarrow \text{Na}^+ + \text{OH}^- \]
Khatello ea li-OH-ion ka har'a tharollo e tšoana le khatello ea NaOH, e leng 0.001 M.
\[ [OH^-] = 0.001 \, \mongolo{M} = 10^{-3} \, \mongolo{M} \]
Bala pOH pele:
\[ \text{pOH} = -\log[OH^-] = -\log{10^{-3}} = 3 \]
Fetolela pOH ho pH:
\[ \mongolo{pH} = 14 – \mongolo{pOH} = 14 – 3 = 11 \]
Kahoo, pH ea tharollo ea NaOH ea 0.001 M ke 11.
Mohlala oa Potso ea 3: Asiti ea Sulfuric (H2SO4)
> Bala pH ea tharollo ea 0.01 M H2SO4.
Puisano:
H2SO4 ke asiti e matla e nang le mekhahlelo e 'meli ea ionization. Mokhahlelo oa pele:
\[ \text{H2SO4} \rightarrow \text{H}^+ + \text{HSO4}^- \]
Sephetho sa ionization ea mohato oa pele se lekana le khatello ea H2SO4 ea 0.01 M bakeng sa H+ le HSO4^- ka 'ngoe. Leha ho le joalo, mohato oa pele o hlahisa li-ion tse peli tsa H+ ho tsoa molek'huleng e le 'ngoe ea H2SO4.
Kahoo, kakaretso ea [H+] e tla ba habeli ea mahloriso a pele:
\[ [H^+] = 2 \makgetlo 0.01 = 0.02 \]
Ho sebelisa foromo ea pH:
\[ \text{pH} = -\log{[H^+]} = -\log{0.02} = -\log{2 \times 10^{-2}} = -(\log{2} + \log{10^{-2}}) \]
Bakeng sa tsebo ea hau,
\[ \log{2} \hoo e ka bang 0.301 \]
Kahoo:
\[ \mongolo{pH} = -(0.301 + (-2)) = 1.699 \]
Kahoo, pH ea tharollo ea 0.01 M H2SO4 e ka ba 1.699.
Mohlala oa Potso ea 4: Motheo o Matla (Ca(OH)2)
> Bala pH ea tharollo ea 0.005 M Ca(OH)2.
Puisano:
Ca(OH)2 ke motheo o matla mme molek'hule ka 'ngoe e fana ka li-OH-ion tse peli:
\[ \text{Ca(OH)2} \rightarrow \text{Ca}^{2+} + 2\text{OH}^- \]
Khatello ea OH- e tla ba habeli khatello ea Ca(OH)2 hobane molek'hule ka 'ngoe ea Ca(OH)2 e hlahisa OH- tse peli. Kahoo,
\[ [OH^-] = 2 \makgetlo 0.005 = 0.01 \, \mongolo{M} \]
Bala pOH pele:
\[ \text{pOH} = -\log{[OH^-]} = -\log{0.01} = -\log{10^{-2}} = 2 \]
Fetolela pOH ho pH:
\[ \mongolo{pH} = 14 – \mongolo{pOH} = 14 – 2 = 12 \]
Kahoo, pH ea tharollo ea 0.005 M Ca(OH)2 ke 12.
Qetello
Sehloohong sena, re buisane ka mokhoa oa ho bala pH bakeng sa mehlala e 'maloa ea litharollo tsa asiti e matla le motheo o matla. Hopola hore bakeng sa li-acid kapa metheo e matla, re nahana hore li entsoe ka ion ka botlalo tharollong. Ka hona, mahloriso a li-ion tsa H+ bakeng sa asiti e matla le li-ion tsa OH bakeng sa motheo o matla a tla lekana le mahloriso a pele a asiti kapa motheo, kamora ho fetola lintlha tsa stoichiometric haeba ho hlokahala. Sena se nolofatsa lipalo tsa pH ho sebelisoa mekhoa ea motheo ea pH le pOH.
Ho utloisisa mohopolo ona ho bohlokoa, haholo-holo ts'ebelisong ea lik'hemik'hale, ebang ke laboratoring ea k'hemistri, indastering, kapa bophelong ba letsatsi le letsatsi. Ka boikoetliso le kutloisiso e tiileng, ho bala pH ea li-acid tse matla le metheo e tla ba mosebetsi o bonolo.
