From the data given in the following table,
| Ion | OH- | Cl- | Br- | \(\mathrm{SO}_4^{2-}\) |
| Ionic mobility (× 10-8 m2 S-1 V-1) | 20.6 | 7.9 | 8.1 | 8.3 |
the correct order for an effective radius of the anions in water at 25°C is
1
OH- < \(\mathrm{SO}_4^{2-}\) < Br- < Cl -
2
OH- > \(\mathrm{SO}_4^{2-}\) > Br- > Cl -
3
OH- < Cl- < Br- < \(\mathrm{SO}_4^{2-}\)
4
OH- > Cl- > Br- > \(\mathrm{SO}_4^{2-}\)