Question

Describe how to prepare 250mLof 1.00M ammonia bufferpH9.00 starting with 28 wt %${\mathbf{NH}}_{\mathbf{3}}$(“concentrated ammonium hydroxide” listed on the back inside cover of the book) and “concentrated”HCI(37.2 wt %)or “concentrated” NaOH(50.5wt%)

Short answer

The steps are:

1. Place 16.9m L of 28wt%${\mathrm{NH}}_3$ in a beaker filled with 160m L of ${\mathrm{H}}_2\mathrm{O}$

2. Add 9mL of 37.2wt%HCI and monitor the with an electrode while adding 3mLHCI until the pH = 9.00

3. Transfer the solution to a 250 - mL volumetric flask and dilute to the volume of 250 mL .

Step-by-step solution

 Define pH

Hydrogen potential is referred to as pH. On a scale from 0 to 14, it represents the logarithm of the reciprocal of the hydrogen ion concentration in gram atoms per liter and is used to express the acidity and alkalinity of a solution.

Considering Ammonia and Hydrochloric acid  

Start with 28wt%${\mathrm{NH}}_3$ (concentrated ammonia hydroxide) and concentrated HCI(37.2wt%) or concentrated NaOH(50.5 wt\%)

Final steps for preparing 250mL of 1.00M ammonia buffer pH9.00

The steps are:

1. Place 16.9m L of 28wt%${\mathrm{NH}}_3$in a beaker filled with 160m L of ${\mathrm{H}}_2\mathrm{O}$

2. Add 9m L of 37.2wt%HCI and monitor the pH with an electrode while adding until the

3. Transfer the solution in a 250 - m L volumetric flask and dilute to the volume of 250mL .