C, 0.746 mol Ag.
1 mol Ag = 6.022 x 1023 atoms of Ag -> 4.49 x 1023 atoms of Ag x 1mol Ag/6.022 x 1023 atoms -> 0.746 mol Ag
MgO
MgI2
PbO2
PbI4
These are the possible compounds
In carbohydrates the C:H:O is 1:2:1
The student was not successful.
Consider the standard reduction potentials.
Li⁺ + e⁻ ⇌ Li; E° = -3.04 V
2H₂O + 2e⁻ ⇌ H₂ + 2OH⁻; E° = -0.83 V
To reduce Li⁺ to Li, the student must apply 3.04 V.
However, it takes only 0.83 V to reduce water to hydrogen.
Thus, the student will get H₂ instead of Li.