What is the answer please hurry

In numbering carbon atoms in the parent chain of a hydrocarbon, why would you number from right to left, rather than left to right

How do i complete this electrolysis of water lab? i’m at home, so i don’t have the materials, and the lab didn’t properly work and was incomplete at school.

What is the chemical name of the compound na2co3? use the list of polyatomic ions and the periodic table to you answer. a. sodium carbon oxide b. sodium carbonate c. sodium(ll) carbonate d. sodium oxalate