15 grams of NaCl are added to a beaker. It is dissolved in 200 ml of water

and diluted up to 250 ml. What is the Na + concentration in moles/liter in the

final solution? (Atomic mass are Na = 22.99 g/mole, Cl=35.45 g/mol)

1,024 moles/liter

Explanation:

MNaCl: 58,44

nNaCl: 15g/58,44 g/mole = 0,256 mole

When NaCl dissolves in water it ionizes. After ionization of 1 mole of NaCl, in the 1 mole of Na + and 1 mole of Cl - ions will be present in the medium.

NaCl (s) = > Na + (aq) + Cl - (aq)

For this case 0,256 moles of Na + ion will be present in the medium.

Concentration of Na + = 0,256 moles / 0,250 L of water = 1,024 moles/liter