Question

compute the no. of ions present in 5.85g of NaCl

Answer 1

I mole of nacl contains 2 ions
23+35.5=58.5g
therefore, 58.5 gives 2ions
1 g will give 2/58.5
5.85 g will give =2/58.5*5.85
which comes to be 0.2 ions

Answer 2

1 mole of NaCl = 58.5 g
x moles of NaCl = 5.85 g
By cross-multiplication , we get
5.85/58.5 = 0.1 moles
1 NaCl contains 1 Na+ ion and 1 Cl- ion, a total of 2 ions.
Thus 1 mole of NaCl contains 2*(Avogadro Number) of ions
=> 0.1 moles contains 0.2*(Avogadro Number) ions = 1.2 x 10^23 ions