Question

The concentration of water molecules in pure water at 298 K is?

Options

• 7.26 M

• 1 × 10^–7 M

• 10⁷ M

• 55.5 M

Answer 1

55.5 M

Explanation:

Number of moles of water in 1000 mL of water

n = `(1000  g)/((18  g)/(mol))` = 55.5 mol

Concentration = `n/V`

= `(55.5  mol)/(1  dm^3)`

= 55.5 mol / dm³