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Dissociation constants of acids: HOAc Ka=1.78x10-5 H2SO4 Ka1=1x107 Ka2=1.0x10-2

ID: 1021095 • Letter: D

Question

Dissociation constants of acids: HOAc Ka=1.78x10-5 H2SO4 Ka1=1x107 Ka2=1.0x10-2 HCNO Ka=2x10-4 H2CO3 Ka1=4.3x10-7 Ka2=5.6x10-11 H2O Ka=1.0x10-14 HIO Ka=2.3x10-11 HIO3 Ka = 1.7x10-4 HCl Ka=1x108 HNO3 Ka=1x106 HF Ka = 3.5x10-4 H2C2O4 Ka1 = 6.0x10-2 Ka2 = 6.1x10-5 Dissociation constants of bases: NH3 Kb=1.76x10-5 CH3NH2 Kb=4.4x10-4 HONH2 Kb=1.1x10-8 C2H5NH2 Kb = 5.6x10-4

7a- I mix 500 mL of 0.250 M HCNO with 250 mL of 0.333 M NaCNO. What is the concentration of HCNO?

7b-I mix 500 mL of 0.250 M HCNO with 250 mL of 0.333 M NaCNO. What is the concentration of CNO- ?

7c-I mix 500 mL of 0.250 M HCNO with 250 mL of 0.333 M NaCNO. Construct the ICE chart for the Ka reaction of HCNO for this particular mixture. [Don’t solve, just set it up.]

Explanation / Answer

Initial                                                   Final

M1 = 0.25M                                        M2 =

V1 = 500ml                                        V2 = 500+250 = 750ml

     M1V1     =   M2V2

        M2   = M1V1/M2

               = 0.25*500/750 = 0.166M

7b .

Initial                                                   Final

M1 = 0.333M                                        M2 =

V1 = 250ml                                        V2 = 500+250 = 750ml

     M1V1     =   M2V2

        M2   = M1V1/M2

               = 0.33*250/750 = 0.11M