Question

Consider a weak base \(B\) of \(pK_b = 5.699\). \(x\) 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 \(25^\circ\text{C}\). The values of \(x\) and \(y\) respectively are

• A. \(x=42.7,\ y=57.3\)
• B. \(x=11.1,\ y=88.9\)
• C. \(x=85.7,\ y=14.3\)
• D. \(x=14.3,\ y=85.7\)

Hint:

For basic buffers, always convert \(pK_b\) to \(pK_a\) before using the Henderson–Hasselbalch equation.

Answer 1

The Correct Option is D