Question

2.6×10^-3 kg of sodium hydroxide (molar mass 40g mole^-1 )is dissolved in 5×10^2cm^3 of water. Calculate molarity of NaOH solution.

Answer 1

Given,

Mass of the Sodium Hydroxide = 2.6 × 10⁻³ kg = 2.6 g.

Molar mass = 40 g/mole.

∴ No. of moles = Mass/Molar Mass

∴ No. of moles = 2.6/40

∴ No. of moles = 0.065 moles.

Volume of the solution = 5 × 10²cm³ = 0.5 liter.

Using the formula,

Molarity = No. of moles/Volume of the solution.

∴ Molarity = 0.065/0.5

∴ Molarity = 0.13 M.

Hope it helps.