first, molecular mass of Zn=65 g
molecular mass of HNO3=63 g
in the given reaction,
10 × 63 g HNO3 reacts with 4×65 g Zn.
i.e. 1.49 g HNO3 reacts with (260/630) ×1.49
=0.61 g Zn.
now the number of moles in Zn is
given mass/ molecular mass=0.61/65=0.0093 moles
Again,
no. of atoms= 0.0093× 6.023×+0^23
=5.6×10^21 atoms
