Qhov Tseem Ceeb Qhov txawv - Acidity vs Basicity
Acidity thiab hauv paus ntawm cov tebchaw yog qhov qhia txog pH. Acidity ntawm qhov nruab nrab yog tshwm sim los ntawm acidic compounds, uas tuaj yeem tso tawm hydrogen ions (H+), ua rau pH qis hauv qhov nruab nrab. Lub hauv paus ntawm qhov nruab nrab yog tshwm sim los ntawm cov ntsiab lus yooj yim, uas tuaj yeem tso tawm hydroxide ions (OH –), ua rau muaj pH siab hauv qhov nruab nrab. Qhov sib txawv tseem ceeb ntawm acidity thiab qhov pib yog tias acidity ua rau pH qis thaum qhov pib ua rau pH siab hauv qhov nruab nrab aqueous.
Acidity yog dab tsi?
Acidity yog qib ntawm cov kua qaub hauv cov khoom. Qhov concentration ntawm hydrogen ions (H+) yog qhov tseem ceeb siv los txheeb xyuas acidity. Lub hydrogen ion concentration yog qhia raws li tus nqi pH. pH yog qhov tsis zoo logarithm ntawm hydrogen ion concentration. Yog li, siab dua cov hydrogen ion concentration, txo cov pH. Tus nqi pH qis qhia tias muaj acidity ntau dua.
Raws li cov kua qaub ntawm cov tshuaj, muaj ob hom kua qaub li cov kua qaub uas muaj zog thiab tsis muaj zog acids. Cov kua qaub muaj zog ua rau cov kua qaub ntau dua hauv cov dej nruab nrab thaum cov kua qaub tsis muaj zog ua rau cov kua qaub qis. Cov kua qaub muaj zog tuaj yeem sib cais tag nrho rau hauv ions, tso tawm tag nrho cov hydrogen ions (H+). Nyob rau hauv sib piv, ib tug qaug zog acid ib feem dissociates, tso ib co hydrogen ions. Cov kua qaub kuj tuaj yeem muab faib ua monoprotic acids thiab polyprotic acids; monoprotic acids tso ib hydrogen ion ib molecule whereas polyprotic acids tso ntau hydrogen ions ib molecule.
Cov kua qaub ntawm cov kua qaub yog txiav txim siab los ntawm pKa ntawm cov kua qaub. pKa yog lub logarithm tsis zoo ntawm Ka. Ka yog cov kua qaub dissociation tas li ntawm kev daws. Nws yog ib qho kev ntsuas ntau ntawm lub zog ntawm cov kua qaub hauv cov kua (lossis acidity). Txo cov pKa, cov kua qaub muaj zog dua. Cov pKa siab dua, cov kua qaub qis dua.
Daim duab 01: Txiv qaub kua txiv muaj acidity siab
Lub sijhawm hloov pauv ntawm acidity ntawm cov tshuaj lom neeg feem ntau nyob ntawm lawv cov txiaj ntsig electronegativity. Lub electronegativity ntawm cov khoom siv tshuaj nce ntawm sab laug mus rau sab xis ntawm ib lub sijhawm. Yog hais tias lub electronegativity ntawm ib lub atom siab dua, nws muaj peev xwm stabilize ib tug tsis zoo atom ntawm nws yooj yim heev vim hais tias nws muaj ib tug ntau affinity rau electrons. Yog li ntawd, cov hydrogen ions txuam nrog siab electronegative atoms tau yooj yim tso tawm tsawg dua electronegative atoms, uas ua rau acidity ntau dua. Thaum mus rau hauv ib pab pawg neeg nyob rau hauv lub sij hawm lub sij hawm, lub acidity nce. Qhov no yog vim qhov loj ntawm atoms nce hauv pawg. Cov atoms loj tuaj yeem tswj cov nqi tsis zoo rau lawv (los ntawm kev faib cov nqi); li no, hydrogen ion txuam nrog lub atom loj tuaj yeem tso tawm tau yooj yim.
Dab tsi yog qhov yooj yim?
Basicity ntawm ib yam khoom yog tus naj npawb ntawm hydrogen atoms hloov tau los ntawm lub hauv paus hauv ib qho acid. Nyob rau hauv lwm yam lus, lub hauv paus ntawm ib tug compound yog tus naj npawb ntawm hydrogen ions uas tuaj yeem hnov qab tag nrho nrog hydroxide ions tso tawm los ntawm lub hauv paus.
Daim duab 02: Cov Qauv Tshuaj ntawm Hydroxide Ion
Cov yam ntxwv uas tuaj yeem cuam tshuam rau lub hauv paus ntawm kev sib xyaw yog teev hauv qab no.
- Electronegativity
- Atomic radius
- tus nqi raug cai
Electronegativity ntawm ib lub atom hais txog nws txoj kev sib raug zoo rau electrons. Ib lub atom uas muaj electronegativity siab tuaj yeem nyiam cov electrons thaum piv rau cov atoms qis electronegative. Siab dua lub electronegativity, txo qhov hauv paus. Txhawm rau tso tawm hydroxide ion, daim ntawv cog lus hluav taws xob nruab nrab ntawm cov pa atom thiab cov khoom seem ntawm cov molecule yuav tsum tau txais tag nrho los ntawm cov pa atom (cov pa oxygen atom hauv hydroxide pawg yuav tsum muaj electronegative ntau dua li lwm cov atom nws tau sib koom ua ke). Piv txwv li: yog lub hauv paus ntawm ROH siab, lub electronegativity ntawm R yog me dua li ntawm cov pa atom.
Daim duab 03: Cov xab npum yog cov hauv paus tsis muaj zog tsim los ntawm cov tshuaj tiv thaiv fatty acids nrog sodium hydroxide lossis potassium hydroxide.
Atomic radius yog lwm yam uas cuam tshuam rau lub hauv paus ntawm lub compound. Yog hais tias lub atomic radius yog me me, lub electron ceev ntawm lub atom yog siab. Yog li, hydroxide ion tuaj yeem tso tawm tau yooj yim. Tom qab ntawd lub hauv paus ntawm qhov sib xyaw yog qhov sib piv siab.
Tus nqi raug cai feem ntau yog tus nqi zoo lossis tus nqi tsis zoo. Ib tug zoo formal charge qhia ib tug tsawg electron ceev. Yog li ntawd, daim ntawv cog lus electrons tsis tuaj yeem nyiam los ntawm hydroxide ion. Tom qab ntawd nws tsis tuaj yeem tso tawm tau yooj yim (cov hydroxide ion), qhia tias qhov pib qis dua. Hauv qhov sib piv, tus nqi tsis zoo ua rau muaj kev yooj yim dua.
Qhov txawv ntawm Acidity thiab Basicity yog dab tsi?
Acidity vs Basicity |
|
| Acidity yog qib ntawm cov kua qaub hauv cov khoom. | Basicity yog hais txog lub xeev ntawm kev ua lub hauv paus, uas tuaj yeem tso tawm hydroxide ions (OH-). |
| pH | |
| Acidity ua rau pH qis hauv cov dej nruab nrab. | Basicity ua rau pH siab hauv cov dej nruab nrab. |
| Ions | |
| Acidity qhia tau hais tias muaj siab ntawm hydrogen ions hauv nruab nrab. | Basicity qhia tau hais tias muaj siab ntawm hydroxide ions hauv nruab nrab. |
| Nyob ib ntus | |
| Cov kua qaub nce ntawm sab laug mus rau sab xis ib ntus thiab nqis ib pawg. | Qhov pib txo qis ntawm sab laug mus rau sab xis ib lub sijhawm thiab nqis ib pab pawg. |
| Kev cuam tshuam ntawm Electronegativity | |
| Acidity siab yog tias electronegativity (ntawm atom uas hydrogen atom sib koom) siab. | Basicity siab yog tias cov electronegativity (ntawm lub atom uas oxygen atom ntawm hydroxide ion yog sib txuas) yog tsawg. |
Summary – Acidity vs Basicity
Acidity thiab hauv paus yog ob lub ntsiab lus siv hauv chemistry. Acidity yog tshwm sim los ntawm acidic compounds. Basicity yog tshwm sim los ntawm cov ntsiab lus sib xyaw. Qhov sib txawv tseem ceeb ntawm acidity thiab qhov yooj yim yog tias acidity ua rau pH qis thaum qhov pib ua rau pH siab hauv qhov nruab nrab aqueous.
