Question

2. A structure of Luminol is shown with all functional groups protonated and their pka labeled. Use words and structures to answer a and b. Luminol pke 2 9 a. Acetic acid was added at the end of the reduction step to obtain a pH of - 3-4.2pts i. Draw the structure of the luminol at pH 3. ii. Refering to the structure in a.i.), explain why the luminol precipitates from the aqueous solution at this pH. NH₂ NH N-H b. The luminol is more soluble in basic solutions (pH >12). 2 pts i. Draw the structure of luminol at pH 12. ii. Referencing the structure in b.i), explain why luminol is more soluble in basic aqueous solution?

Answer 1

Primeiple i pH a af om oced, then it mestly its depronatid foam. e. mains in it pH pk am acid, thun it its potonati d fonm. yemains in NH LPKaz 6.5) HCpkaE ) pha-2 Ns a) P3 pka cs N )5o jit wil 9remaim in duptana i)pH -ted form i-e. NH buty pH pkn af-NH 5 both -NH up wiJA grOmain m theis poto Tnati d fonm ire. -NH Stuneture of lumi nal NH N at pH 3 i) Now, This onm has mo charge Mever, it has lage hyderobhobie pot S it will be Pnimp ble in ahlumimol pocipitatus form aqueous Watr Thatl DOLutiun at this pH b pH 12 59 pHpKa 0f au the 3 toup, 5 au 3 auidie aoups cill 9u main in thep depnotonati d fnm NO wil 9umain as NH and-NH wilA 6touare of bumimo at pH) -NO i) This fnm m has 2 megahive ehange 50, it Iu be solvats by ovent ter. 5 its ubility Thatis why lumimat i me Solubk lutiun 2whe n PH is high in watr wi be high. in basie aneous

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