A sample contains 0.25 mol of NaCl. How many formula units of NaCl are present in the sample?

• A. 2.41 × 10^{22} formula units
• B. 3.01 × 10^{24} formula units
• C. 6.02 × 10^{22} formula units
• D. 1.51 × 10^{23} formula units

Answer: (D)

Verified step by step guidance

1. Understand that the problem asks for the number of formula units in a given amount of moles of NaCl. A formula unit refers to the simplest ratio of ions represented in an ionic compound, here NaCl.
2. Recall Avogadro's number, which is the number of particles (atoms, molecules, or formula units) in one mole of a substance. Avogadro's number is \$6.02 \times 10^{23}$ formula units per mole.
3. Set up the relationship between moles and formula units using Avogadro's number: \(\text{Number of formula units} = \text{moles} \times 6.02 \times 10^{23}\) formula units/mole.
4. Substitute the given amount of moles (0.25 mol) into the equation: \(\text{Number of formula units} = 0.25 \times 6.02 \times 10^{23}\) formula units.
5. Perform the multiplication to find the total number of formula units in the sample.