Question

Find no of mole & no. of each atom present in 1.25 mole of NH2​

Answer 1

I'm assuming you mean no. of atoms in 1.25 mol of NH3.

As one mol of NH3 contains 6.023 X 10^23 molecules, hence 1 mol of NH3 contains 6.023 X 10^23 X 4 atoms.

Hence: 1.25 mol of NH3 contains (6.023 X 10^23 X 4 X1.25)=3.0115 X 10^24 atoms.