Which of the following has the maximum number of atoms?

Which of the following has the maximum number of atoms?

Calculate the molar mass of the following substances.
$(a)$ Phosphorus molecule,$P_4$ (Atomic mass of phosphorus $= 31$)
$(b)$ Hydrochloric acid,$HCl$
$(c)$ Nitric acid,$HNO_3$

Define formula unit mass of a compound. Calculate the formula unit mass of:
$(a)$ $Na_{2}CO_{3} \cdot 10H_{2}O$
$(b)$ $CuSO_{4}$
(Given atomic mass of $Na = 23 \text{ u}, C = 12 \text{ u}, O = 16 \text{ u}, Cu = 63.5 \text{ u}, S = 32 \text{ u}, H = 1 \text{ u}$)

$A$ silver ornament of mass $m \, g$ is polished with gold equivalent to $1\%$ of the mass of silver. Compute the ratio of the number of atoms of gold and silver in the ornament.

Calcium chloride when dissolved in water dissociates into its ions according to the following equation:
$CaCl_{2}(aq) \rightarrow Ca^{2+}(aq) + 2Cl^{-}(aq)$
Calculate the number of ions obtained from $CaCl_{2}$ when $222 \, g$ of it is dissolved in water.