Question

In: Chemistry

In a titration of 46.24 mL of 0.3359 M ammonia with 0.3359 M aqueous nitric acid,...

In a titration of 46.24 mL of 0.3359 M ammonia with 0.3359 M aqueous nitric acid, what is the pH of the solution when 46.24 mL of the acid have been added?

Solutions

Expert Solution

we have:

Molarity of HNO3 = 0.3359 M

Volume of HNO3 = 46.24 mL

Molarity of NH3 = 0.3359 M

Volume of NH3 = 46.24 mL

mol of HNO3 = Molarity of HNO3 * Volume of HNO3

mol of HNO3 = 0.3359 M * 46.24 mL = 15.532 mmol

mol of NH3 = Molarity of NH3 * Volume of NH3

mol of NH3 = 0.3359 M * 46.24 mL = 15.532 mmol

We have:

mol of HNO3 = 15.532 mmol

mol of NH3 = 15.532 mmol

15.532 mmol of both will react to form NH4+ and H2O

NH4+ here is strong acid

NH4+ formed = 15.532 mmol

Volume of Solution = 46.24 + 46.24 = 92.48 mL

Ka of NH4+ = Kw/Kb = 1.0E-14/1.8E-5 = 5.556*10^-10

concentration ofNH4+,c = 15.532 mmol/92.48 mL = 0.1679 M

NH4+ + H2O -----> NH3 + H+

0.1679 0 0

0.1679-x x x

Ka = [H+][NH3]/[NH4+]

Ka = x*x/(c-x)

Assuming small x approximation, that is lets assume that x can be ignored as compared to c

So, above expression becomes

Ka = x*x/(c)

so, x = sqrt (Ka*c)

x = sqrt ((5.556*10^-10)*0.1679) = 9.659*10^-6

since c is much greater than x, our assumption is correct

so, x = 9.659*10^-6 M

[H+] = x = 9.659*10^-6 M

we have below equation to be used:

pH = -log [H+]

= -log (9.659*10^-6)

= 5.01

Answer: 5.01


Related Solutions

In a titration of 44.86 mL of 0.3356 M ammonia with 0.3356 M aqueous nitric acid,...
In a titration of 44.86 mL of 0.3356 M ammonia with 0.3356 M aqueous nitric acid, what is the pH of the solution when 44.86 mL of the acid have been added?
15 a) In a titration of 41.34 mL of 0.3483 M ammonia with 0.3503 M aqueous...
15 a) In a titration of 41.34 mL of 0.3483 M ammonia with 0.3503 M aqueous nitric acid, what is the pH of the solution when 5.00 mL of the acid have been added? b) In a titration of 44.50 mL of 0.3082 M ammonia with 0.3082 M aqueous nitric acid, what is the pH of the solution when 44.50 mL of the acid have been added?
20. An aqueous solution of nitric acid is standardized by titration with a 0.162 M solution...
20. An aqueous solution of nitric acid is standardized by titration with a 0.162 M solution of potassium hydroxide. If 27.1 mL of base are required to neutralize 20.7 mL of the acid, what is the molarity of the nitric acid solution? M nitric acid
1.) Determine the pH during the titration of 22.7 mL of 0.316 M nitric acid by...
1.) Determine the pH during the titration of 22.7 mL of 0.316 M nitric acid by 0.111 M barium hydroxide at the following points: (1) Before the addition of any barium hydroxide (2) After the addition of 16.2 mL of barium hydroxide (3) At the equivalence point (4) After adding 41.8 mL of barium hydroxide 2.) Determine the pH during the titration of 28.1 mL of 0.256 M perchloric acid by 0.139 M barium hydroxide at the following points: (1)...
In a titration of 44.50 mL of 0.3082 M nitrous acid with 0.3082 M aqueous sodium...
In a titration of 44.50 mL of 0.3082 M nitrous acid with 0.3082 M aqueous sodium hydroxide, what is the pH of the solution when 44.50 mL of the base have been added?
In a titration of 44.50 mL of 0.3082 M nitrous acid with 0.3082 M aqueous sodium...
In a titration of 44.50 mL of 0.3082 M nitrous acid with 0.3082 M aqueous sodium hydroxide, what is the pH of the solution when 44.50 mL of the base have been added?
In a titration of 35.61 mL of 0.3889 M nitrous acid with 0.3889 M aqueous sodium...
In a titration of 35.61 mL of 0.3889 M nitrous acid with 0.3889 M aqueous sodium hydroxide, what is the pH of the solution when 35.61 mL of the base have been added?
In a titration of 40.55 mL of 0.3137 M nitrous acid with 0.3137 M aqueous sodium...
In a titration of 40.55 mL of 0.3137 M nitrous acid with 0.3137 M aqueous sodium hydroxide, what is the pH of the solution when 40.55 mL of the base have been added?
In a titration of 47.76 mL of 0.3886 M nitrous acid with 0.3886 M aqueous sodium...
In a titration of 47.76 mL of 0.3886 M nitrous acid with 0.3886 M aqueous sodium hydroxide, what is the pH of the solution when 47.76 mL of the base have been added?
In a titration of 47.63 mL of 0.3786 M nitrous acid with 0.3786 M aqueous sodium...
In a titration of 47.63 mL of 0.3786 M nitrous acid with 0.3786 M aqueous sodium hydroxide, what is the pH of the solution when 47.63 mL of the base have been added?
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT