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to make 500.0 mL of solution? s the pH of solution when 25.5 g NaC2H,O2 is added

ID: 1026669 • Letter: T

Question

to make 500.0 mL of solution? s the pH of solution when 25.5 g NaC2H,O2 is added to 0.550 M HC HsO e pH of after adding 0.0060 mol HCI to 0.300 L of a buffer solution that is 0.250 M HC2H O2 and 0.560 M NaC2H3O2? (k) What is the pH of after adding 0.0060 mol NaOH to 0.300 L of a buffer solution that is 0.250 M HC2Hs02 and 0.560 M Na C2H302? (C) What is the pH of a solution containing 50.00 mL of 0.100 M HCI to which 30.00 mL of 0.100 M NaOH has been added? (m) What is the pH of a solution containing 50.00 mL of 0.100 M HCl to which 50.00 (n) What is the pH of a solution containing 50.00 mL of 0.100 M HCl to which 60.00 o) What is the pH of a solution that contains 50.00 mL of 0.10 M NH3 to which ) What is the pH of a solution that contains 50.00 mL of 0.10 M NHs to which What is the pH of a solution that contains 50.00 mL of 0.10 M NHs to which mL of 0.100 M NaOH has been added? mL of 0.100 M NaOH has been added? 30.00 mL of 0.10 M HCI has been added? 50.00 mL of 0.10 M HCI has been added? 60.00 mL of 0.10 M HCI has been added?

Explanation / Answer

1.

mass of NaC2H3O2 = 25.5 grams

molar mass of NaC2H3O2= 82.0 gram/mole

nubber of moles of NaC2H3O2= 25.5/82.0 = 0.311 moles

HC2H3O2 = 0.550M of 500 ml

number of moles fo HC2H3O2 = 0.550Mx0.500L= 0.275 moles

PKa of HC2H3O2= 4.76

PH= PKa + log[salt]/[acid]

PH= 4.76 + log(0.311/0.275)

PH=4.81

J) number of moles of HCl= 0.0060 moles

number of moles of NaC2H3O2 = 0.560M x0.3L = 0.168 moles

number of moles of HC2H3O2 = 0.250Mx0.3L= 0.075 moles

after addition o f HCl

number of moles of HC2H3O2 = 0.075 + 0.0060 =0.081 moles

number of moles of NaC2H3O2 = 0.168 - 0.0060 = 0.162 moles

PH= 4.76 + log(0.162/0.081)

PH= 5.06

K)

number of moles of NaOH= 0.0060 moles

number o fmoles of HC2H3O2 = 0.250Mx0.300L= 0.075 moles

number of moles of NaC2H3O2 = 0.560M x0.3L = 0.168 moles

after additon of NaOH

number of moles of HC2H3O2 = 0.075 - 0.006 =0.069 moles

number of moles of NaC2H3O2 = 0.168 + 0.006= 0.174 moles

PH= 4.76 + log(0.174/0.069)

PH= 5.16

l)

number of moles of HCl=0.1Mx0.050L=0.005moles

number of moles of NaOH= 0.1Mx0.03L=0.003 moles

number of moles of HCl is greaterthan the NaOH.

so the solution has acidic nature ;

remaining number of moles of HCl = 0.005 - 0.003 = 0.002 moles

total volume = 50.0+30.0= 80.0ml=0.080L

[H+]= 0.002/0.080=0.025 M

-log[H+]= -log(0.025)

PH= 1.60