Question

In: Chemistry

Denis titrates 25 mL of a 0.060 M solution of ammonia (NH3) with a 0.020 M...

Denis titrates 25 mL of a 0.060 M solution of ammonia (NH3) with a 0.020 M solution of hydrochloric acid. A) Write the chemical equation that occurs B) Do you expect the pH of the solution to be acidic, basic or neutral at the equivalence point? Explain. C) Calculate the pH after 20 mL of HCl solution have been added. Hint: Kb(NH3)=1.8*10-5

Solutions

Expert Solution

A)

chemical equation :

NH3 + HCl -------------------> NH4Cl

B)

pH of solution will be acidic

because at equivalence point the salt NH4Cl is formed . it is the salt of weak base and strong acid . so the pH is less than 7

C )

millimoles of NH3 = 25 x 0.06 = 1.5

millimoles of HCl = 0.02 x 20 = 0.4

NH3    +   HCl ----------------> NH4Cl

1.5            0.4                         0

1.1           0.0                          0.4

pKb =-log Kb = -log (1.8 x 10^-5) = 4.74

pOH = pKb + log [NH4Cl / NH3]

pOH = 4.74 + log (0.4 / 1.1)

pOH = 4.30

pH + pOH = 14

pH = 9.70


Related Solutions

A chemist titrates 200.0mL of a 0.7669M ammonia NH3 solution with 0.4750M HBr solution at 25°C...
A chemist titrates 200.0mL of a 0.7669M ammonia NH3 solution with 0.4750M HBr solution at 25°C . Calculate the pH at equivalence. The pKb of ammonia is 4.75 . Round your answer to 2 decimal places.
A 200 mL solution of 0.100 M solution of Ammonia, NH3 , is slowly mixed with...
A 200 mL solution of 0.100 M solution of Ammonia, NH3 , is slowly mixed with 0.100 M HCl. Determine the pH after addition of: 0 mL of HCl, 50 mL of HCl, 100 mL of HCl, 200 mL of HCl, 250 mL of HCl 4. Describe in exact detail (including gram quantities and identity of species) how you would create a 500 mL solution of buffer with a pH 8.0 ?    
A 200 mL solution of .100 M solution of Ammonia, NH3, is slowly mixed with .100...
A 200 mL solution of .100 M solution of Ammonia, NH3, is slowly mixed with .100 M HCl. Determine the pH after addition of: 0 ml of HCl, 50 mL of HCl, 100 mL of HCl, 200 mL of HCl, and 250 mL of HCl.
A 200 mL solution of .100 M solution of Ammonia, NH3, is slowly mixed with .100...
A 200 mL solution of .100 M solution of Ammonia, NH3, is slowly mixed with .100 M HCl. Determine the pH after addition of: 0 ml of HCl, 50 mL of HCl, 100 mL of HCl, 200 mL of HCl, and 250 mL of HCl.
Equal volumes of a 0.020 M Zn^2+ solution and a 2.0 M NH3 solution are mixed....
Equal volumes of a 0.020 M Zn^2+ solution and a 2.0 M NH3 solution are mixed. Kf for [Zn(NH3)4]^2+ is 4.1 × 10^8. If enough sodium oxalate is added to make the solution 0.10 M in oxalate, will ZnC2O4 precipitate? What is Q? Ksp ZnC2O4 = 2.7 × 10^-8 Answer: no, Q = 2.9 × 10^-12
An aqueous solution contains 0.419 M ammonia (NH3). How many mL of 0.305 M perchloric acid...
An aqueous solution contains 0.419 M ammonia (NH3). How many mL of 0.305 M perchloric acid would have to be added to 150 mL of this solution in order to prepare a buffer with a pH of 9.380. mL
Calculate the ph of a solution that is 0.30 M in ammonia (NH3) and 0.20 M...
Calculate the ph of a solution that is 0.30 M in ammonia (NH3) and 0.20 M in ammonium chloride. Kb=1.76 x 10^-5 Then calculate the ph if you add 10 mL of 1.0 M HCl to 50 mL of your solution in the problem above.
A chemist titrates 210.0 mL of a 0.7560 M butanoic acid (HC3H7CO2) solution with 0.6335 M...
A chemist titrates 210.0 mL of a 0.7560 M butanoic acid (HC3H7CO2) solution with 0.6335 M KOH solution at 25 degrees celsius. Calculate the pH at equivalence. The pKa of butanoic acid is 4.82. Round your answer to 2 decimal places please
A 50.0 mL solution of 0.200 M ammonia (pKa of ammonia is 9.24) is titrated by...
A 50.0 mL solution of 0.200 M ammonia (pKa of ammonia is 9.24) is titrated by 0.100 M HCl. Calculate the pH of the solution when, A.) the volume of HCl is 20.00 mL B.) the volume of HCl is 100.0 mL
A 26.9 mL sample of 0.349 M ammonia, NH3, is titrated with 0.262 M hydroiodic acid....
A 26.9 mL sample of 0.349 M ammonia, NH3, is titrated with 0.262 M hydroiodic acid. At the equivalence point, the pH is . Use the Tables link in the References for any equilibrium constants that are required.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT