An increase in equivalent conductance of a strong electrolyte with dilution is mainly due to
increase in number of ions
increase in ionic mobility of ions
100% ionisation of electrolyte at normal dilution
increase in both i.e. number of ions and ionic mobility of ions
Due to dilution, the number of ions will not increase.
An increase in the ionic mobility of ions increases the equivalent conductance of a strong electrolyte.
Due to the strong electrolyte, it is 100% ionised.
So, from above, the increase in the equivalent conductance of a strong electrolyte with dilution is mainly due to the ionic mobility of ions.
Option 2 is correct.