Question

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)​

Answer 1

1,024 moles/liter

Step-by-step 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