Question

Packing of $Na^{+}$ and $Cl^{-}$ ions in sodium chloride is depicted by the given figure. Choose the correct option regarding formula mass of sodium chloride.

• A. In the solid state, sodium chloride does not exist as a single entity
• B. Formula mass of $NaCl$ is $68.0 \,u$
• C. Formula mass of $NaCl$ is the sum of atomic masses of $Na$ and $Cl$
• D. Both (a) and (c)

Answer 1

Answer: (D)

Formula mass of $NaCl =$ Atomic mass of $Na ^{+}$ Atomic mass of $Cl$
$= 23.0 \,u +35.5\,u = 58.5\,u$