How many mole are contained in 3.131x1024 particles?

              5.12 Moles

Explanation:

                      As we know one mole of any substance contains 6.022 × 10²³ particles (atoms, ions, molecules or formula units). This number is also called as Avogadro's Number.

The relation between Moles, Number of Particles and Avogadro's Number is given as,

                          Number of Moles  =  Number of Particles ÷ 6.022 × 10²³

Putting values,

                          Number of Moles  =  3.131 × 10²⁴ Particles ÷ 6.022 × 10²³

                          Number of Moles  =  5.12 Moles

the electrical  conductivity  of asolution  of an electrolyte is measured by determining the resistance of thesolution  between two flat or cylindrical electrodes separated by a fixed distance.

the answer is na (sodium)