Question

Hey guys, I am having a lot of trouble with my homework. Could you please help? I thumbs up anyone who gives a thorough explanation and shows the work! I really need to understand these concepts!

1) Using the data in the table below, which conjugate acid is the weakest acid, given that all solutions (aq., 25 °C) are 0.200 M? Explain your choice! Base Kb CIO- 3.3 x 10-7 CO3-2 1.8 x 10-4 HS- 1.8 x 10-7 NH2CH3 4.4 x 10-4 2) Which of the following aqueous solutions has the lowest [OH-] (aq., 25 °C)? A) a solution with a pH of 3.0 B) a 1 x 10-4 M solution of HNO3 C) a solution with a pOH of 12.0 D) pure water E) a 1 x 10-3 M solution of NH4Cl

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Answer 1

O low the pka value, higher the audic character Price versa. plat Pk6=14 :pka of co 14-pkb pth = - log kh = -log (3:3x107) = 6.48 : pka = 14-6-48= 7.52 Similarly pka of cog? = 14 + log (KG) = 11:26 pka of 45 = 14+ log (kb) = 7.26 pka of NH2 CH₂= 14t dog (ks) = 10.64 An pka value of co? in highest, therefore it in the weakest aid. @ @ " PH + POH=149 : Por of solution - 14-pH = 14-3-11 [OH-] = 10-PH=104 ® [H] COH)=1014 [OH-]= 10-14 10-19 1010 M th) 10-12 = [OH = 10-POH 10 @ for pure water (OH)- 10lm @ PH bị NH t = -1 (Pet 103 ) - ( - 14 -3) PH = 6.13 14-POH [OH) = 10-1787 – 1,35X108M :, lowest COH) concentration - © :. [OH-] = 10

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