Which of the following buffer solution turns invalid on addition of 10 ml of 1 M HCL (1) 100 - Chemistry - Solutions

Question

Which of the following buffer solution turns invalid on addition
of 10 ml of 1 M HCL?
(1) 100 ml having 0 15 M NH3 and NH4CL each
(2) 100 ml having 0 2 M NH3 and NH4CL each
(3) 100 ml having 0 2 M NH3 and 0 1 M NH3 and 0 1 M NH4CL
each
(4) 100 ml having 0 05 M NH3 and 0 1 M NH4CL each

Arti Gujrati · Accepted Answer

The correct answer is 4
When HCl is added to the solution it reacts with NH3 to form
NH4Cl hence do not allow to increase the hydrogen ion conc in
solution and will be change by negligible value
Moles of HCl = conc of HCl * volume in Litre = 1 *10/1000 = 0
01moles
Moles of NH3 (before addition of NH3) = Conc of NH3 * volume of
NH3 in L = 0 05 * 100/1000 = 0 005
This shows that moles of NH3 is less than HCl Hence complete
neutralization of HCl would not take place and solution will
contain excess of H+ ions So the pH of the system will change
drastically Hence this buffer is not valid
You can check the Initial and final values of moles of
NH3 in all cases

Question no
NH3(initial)
NH3(final)

1
0 015
0 005

2
0 03
0 02

3
0 02
0 01

Question no.	NH3(initial)	NH3(final)
1	0.015	0.005
2	0.03	0.02
3	0.02	0.01

Which of the following buffer solution turns invalid on addition of 10 ml of 1 M HCL? (1) 100 ml having 0.15 M NH3 and NH4CL each (2) 100 ml having 0.2 M NH3 and NH4CL each (3) 100 ml having 0.2 M NH3 and 0.1 M NH3 and 0.1 M NH4CL each (4) 100 ml having 0.05 M NH3 and 0.1 M NH4CL each

Which of the following buffer solution turns invalid on addition of 10 ml of 1 M HCL?

(1) 100 ml having 0.15 M NH3 and NH4CL each

(2) 100 ml having 0.2 M NH3 and NH4CL each

(3) 100 ml having 0.2 M NH3 and 0.1 M NH3 and 0.1 M NH4CL each

(4) 100 ml having 0.05 M NH3 and 0.1 M NH4CL each