Question

please help. i will give you a thumbs up

Exercise 6. Which of the following mixtures would create an effective buffer? Give your reasoning in each case. a) 0.10 mol HCl and 0.10 mol NaOH in 1.0L H2O. b) 0.10 mol NH3 and 0.15mol NH4Cl in 1.0L H2O. c) 0.010mol HCN and 0.20mol NaCN 1.0L H2O. d) 0.10 mol NH4Cl and 0.20mol NaCN in 1.0L H20. e) 0.10 mol HCl and 0.20mol NaCN 1.0L H2O.

Answer 1

acidic buffer is formed by weak acid and salt of weak acid
basic buffer is formed by weak base and salt of weak base

a)
HCl is strong acid and NaOH is string base.
They cant form buffer

b)
NH3 is weak base and NH4+ is its conjugate acid.
They will form basic buffer

C)
HCN is weak acid and CN- is its conjugate base.
They will form acidic buffer

d)
NH4+ and CN- are unrelated.
They cant form buffer

e)
Amount of HCN is less.
So, 0.10 mol of CN- will react will all of HCl to form 0.10 mol of HCN.
So, we will have HCN and CN- remaining.
They will form acidic buffer

Answer: b, c, e