What are the concentrations of acetic acid pka 476 and aceta

What are the concentrations of acetic acid (pka 4.76) and acetate in a buffer solution of 0.15 M at pH 4.6? Enter your answer to two significant figures. (For example, 0.0090 and 0.0097 each have two significant figures, whereas 0.009 has only one significant figure.) 0 OH acetic acid acetate Number Number [acetic acid]= acetate] =

Solution

according to hasselbalch hendersen equation

pH = pKa + log [conjugate base / acid]

pH = pKa + log [CH3COO- / CH3COOH]

4.6 = 4.76 + log [CH3COO- / CH3COOH]

log [CH3COO- / CH3COOH] = 4.6 - 4.76

log [CH3COO- / CH3COOH] = -0.16

[CH3COO- / CH3COOH] = 10^(-0.16)

[CH3COO- / CH3COOH] = 0.69183

[CH3COO-] = 0.69183 [CH3COOH]

now

total acetate concentration in the buffer = 0.15

[CH3COO-] + [CH3COOH] = 0.15

0.69183 [CH3COOH] + [CH3COOH] = 0.15

1.69183 [CH3COOH] = 0.15

[CH3COOH ] = 0.089 M

[CH3COO-] = 0.15 - 0.089 = 0.061 M