A 0.01 M acetic acid solution is 1% ionised. An another acetic acid is 10% ionised. What will be the concentration of another acetic acid?

1 Answer
Jan 7, 2018

Answer:

The concentration will be #9 × 10^"-5"color(white)(l) "mol/L"#.

Explanation:

Let #c# be the initial concentration of acetic acid.

The equation for the equilibrium is

#color(white)(m)"HA" + "H"_2"O" ⇌ "A"^"-" + "H"_3"O"^"+"#
#c-αc color(white)(mmmmm) αc color(white)(mml) αc#

The equilibrium concentration of #"HA"# will decrease by #αc#, and those of #"A"^"-"# and #"H"_3"O"^"+"# will be #αc#.

#K = (αc)^2/(c-αc) = (α^2c^2)/(c(1-α)) = (α^2c)/(1-α)#

For the first solution

#K = ((0.01)^2× 0.01)/(1-0.01) = (1 × 10^"-6")/0.99 = 1.0 × 10^"-6"#

For the second solution,

#α^2c = K(1-α)#

#c= (K(1-α))/α^2#

#c = (1.0 × 10^"-6"(1-0.10))/(0.10)^2 = 9 × 10^"-5"color(white)(l) "mol/L"#