The no. Of electrons in 2gm ion of nitrate NO3 is ?

The formula of nitrate ion is NO₃^-.
Number of electrons in 1 mole of NO₃^- ion = (7 + 3 x 8 + 1) x Avagadro's number
  = 32 x Avagadro's number

Now, molar mass of NO₃^- ion  = 14 + 3 x 16 = 62 g/mol
Number of moles in 2 g NO₃^- ion  = 2/62 = 0.032

So, number of electrons in 0.032 moles of NO₃^- ion  = 0.032 x 32 x Avagadro's number
                    = 1.024 x 6.022 x 10²³
  = 6.17 x 10²³