The correct order of nucleophilicity is

Solution

Chemistry ma’am · 3 steps

Same attacking atom, extra negative charge: the anion always beats its neutral partner as a nucleophile.

1. Charge rule. When the attacking atom is the same, the negatively charged species is a stronger nucleophile than its neutral form. The extra electron density makes its lone pair much more ready to be donated.
2. Across a period. When the attacking atoms are different but in the same period, nucleophilicity falls as electronegativity rises. A more electronegative atom holds its lone pairs more tightly, so it shares them less readily.

   Option	Pair compared	Stronger nucleophile	Stated order
   (a)	F⁻ and OH⁻	OH⁻, since O is less electronegative than F	wrong
   (b)	H₂O and OH⁻	OH⁻, the charged form	wrong
   (c)	ROH and RO⁻	RO⁻, the charged form	wrong
   (d)	NH₂⁻ and NH₃	NH₂⁻, the charged form	correct

3. So. The amide ion NH₂⁻ is a stronger nucleophile than ammonia NH₃, so the correct order is (d).

The idea to keep. For the same attacking atom, the anion beats the neutral molecule. For atoms in the same period, the less electronegative atom is the better nucleophile.

Answer from the NTA final answer key. Solution by PrepWiser.