Consider a weak base x’ mL of 0.02 M HCl and ‘y’ mL of 0.02 M weak base ‘B’ are mixed to make 100 mL of a buffer of pH 9 at 25°C. The values of ‘x’ and ‘y’ respectively

Question

Consider a weak base ‘B’ of $p K_{b} = 5.699$ .. ‘x’ mL of 0.02 M HCl and ‘y’ mL of 0.02 M weak base ‘B’ are mixed to make 100 mL of a buffer of pH 9 at 25°C. The values of ‘x’ and ‘y’ respectively are:
$[Given : \log 2 = 0.3010, \log 3 = 0.4771, \log 5 = 0.699]$ [2026]

Smart Achievers · Accepted Answer

(1)

$\begin{matrix} HCl & + & B & \to & {BH}^{+} & + & {Cl}^{-} \\ 0.02 M & 0.02 M \\ x ml & y ml \\ t_{f} & 0 & 0.02 y - 0.02 x & 0.02 x \end{matrix}$

$pOH = p K_{b} + \log [\frac{Salt}{Base}]$

$5 = 5.699 + \log [\frac{Salt}{Base}]$

$\frac{x}{y - x} = \frac{1}{5}$

$6 x = y$

$7 x = 100$

$x = \frac{100}{7} ml$

$and y = \frac{600}{7} ml$

$x$	$y$
14.3	85.7

$x$	$y$
11.1	88.9

$x$	$y$
85.7	14.3

$x$	$y$
42.7	57.3

Solution

Q.
Consider a weak base ‘B’ of $p K_{b} = 5.699$ .. ‘x’ mL of 0.02 M HCl and ‘y’ mL of 0.02 M weak base ‘B’ are mixed to make 100 mL of a buffer of pH 9 at 25°C. The values of ‘x’ and ‘y’ respectively are:
$[Given : \log 2 = 0.3010, \log 3 = 0.4771, \log 5 = 0.699]$ [2026]

1

$x$ $y$

14.3 85.7

2

$x$ $y$

11.1 88.9

3

$x$ $y$

85.7 14.3

4

$x$ $y$

42.7 57.3

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Solution

Q. Consider a weak base ‘B’ of pKb=5.699.. ‘x’ mL of 0.02 M HCl and ‘y’ mL of 0.02 M weak base ‘B’ are mixed to make 100 mL of a buffer of pH 9 at 25°C. The values of ‘x’ and ‘y’ respectively are: [Given: log2=0.3010, log3=0.4771, log5=0.699] [2026]

1 x y 14.3 85.7

2 x y 11.1 88.9

3 x y 85.7 14.3

4 x y 42.7 57.3