A Buffer Is Prepared by Adding 150 ML of 1

question 29

Multiple Choice

A buffer is prepared by adding 150 mL of 1.0 M NaOH to 250 mL of 1.0 M NaH₂PO₄. How many moles of HCl must be added to this buffer solution to change the pH by 0.18 units?

• A) 0.025 mol HCl
• B) 0.063 mol HCl
• C) 0.082 mol HCl
• D) 0.50 mol HCl
• E) 1.0 mol HCl

---

Definitions:

Phospholipids

A class of lipids that form the primary structural component of cellular membranes, characterized by a hydrophobic tail and hydrophilic head.

Hydrophilic Region

A part of a molecule that has affinity for water and can form hydrogen bonds with water molecules.

Hydrophobic Region

A part of a molecule that is repelled by water and typically soluble in nonpolar solvents.

Hydrogen Bond

A weak bond formed between a hydrogen atom in one molecule and an electronegative atom, such as oxygen or nitrogen, in another molecule, important in the structure of water and biological molecules.