Question

How 0.5 moles of naoh and 0.5 m of naoh is different?

Answer 1

0.5 m means 0.5 moles or
$3 .0\times {10}^{23} molecules$
naoh dissolved in 1 kg of solvent.
And simply 0.5 moles means
$3.0 \times {10}^{23} molecules$ naoh