All of the atoms of a saturated hydrocarbon are bonded by how many pair(s) of electrons

All of the atoms of a saturated hydrocarbon are bonded by 4 pairs of electrons in case of a carbon and 1 pair in case of hydrogen. 
Saturated hydrocarbons are hydrocarbons with only single bonds. Each carbon has a maximum number of hydrogen atoms bonded to it. A good example is alkanes. On the other hand the unsaturated hyrocarbon are hydrocarbons with at least one double bond or triple bond.

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The activity series is shown in the attached picture. if the element is below the other, then you can displace the other. following the activity series as a guide, the reactions are as follows: nickel and aluminum chloride3 ni + 2 alcl₃  → 3 nicl₂ + 2 albarium and copper bromideba + cubr  →  no reaction because cu is less oxidizable than bapotassium nitrate and aluminum3 kno₃ + al  → al(no₃)₃ + 3 ksodium phosphate and zincnaso₄ + zn  → znso₄ + na