We know that Avogadro number = 6.02 × 10²³.

Given that rate of distribution = 10¹⁰ grains per second.

Thus, time required to distribute one Avogadro number of wheat grains: -

= Avogadro number / rate of distribution

= 6.023 x 10¹³ s

=1.909 x 10⁶ years

Hence, the time taken to distribute one Avogadro number of wheat grains is 1.909 x 10⁶ years.