The ion having highest mobility in aqueous solutionis

The ion having highest mobility in aqueous solution is

Which alkali metal ion has lowest mobility in aqueous solution ?

Assertion : Li^(+) ions has the lowest mobility in aqueous solution Reason : Li^(+) ion has very high ionisation enthalpy.

Which of the following alkaline earth metals has highest ionic mobility in aqueous solution?

Which of the following alkaline earth metal ion has lowest ionic mobility in aqueous solutions ?