The molar mass of NaCl = The atomic weight of Na + The atomic weight of Cl

Atomic weight; Na = 22.99 g, Cl = 35.45 g

Thus, molar mass of NaCl = 23 + 35.5 = 58.5g/mole.

The number of moles =

Each NaCl particle contains one Na⁺ and one Cl^– ion = 2 ions

Total moles of ions = 0.1 × 2 = 0.2 moles

Number of ions = total number of moles of ions X Avogadro's number

Therefore,

No. of ions = 0.2 × 6.022 ×10²³

= 1.2042 ×10²³ ions