QUESTION 3 OF 10 How is soil different from sedimentary rock?
Soil has been compressed and cemented. Soil can be made out of silt, sand and clay.
Soil is made from weathered rocks. Soil is a mixture of rock particles of different sizes.

1 electron has charge =1.602* 10⁻¹⁹ C
1 mole of electrons have 1.602* 10⁻¹⁹*6.02*10²³C = 9.64*10⁴ C/1mol

One ion Co²⁺   takes 2e⁻ to become Co⁰.
1 mol of Co²⁺  ions take 2 mole of e⁻ to become Co⁰, so
 0.30 mol Co²⁺  ions take mole of 0.60 mol e⁻ to become Co⁰

9.64*10⁴(C/1mol) *0.60 (mol)≈ 5.8 *10⁴ Coulombs.
Correct answer is C