Answer:
Na.
Explanation:
- The oxidation-reduction reaction contains a reductant and an oxidant (oxidizing agent).
- An oxidizing agent, or oxidant, gains electrons and is reduced in a chemical reaction. Also known as the electron acceptor, the oxidizing agent is normally in one of its higher possible oxidation states because it will gain electrons and be reduced.
- A reducing agent (also called a reductant or reducer) is an element (such as calcium) or compound that loses (or "donates") an electron to another chemical species in a redox chemical reaction.
<em>2Na + S → Na₂S.</em>
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Na is oxidized to Na⁺ in (Na₂S) (loses 1 electron). "reducing agent".
S is reduced to S²⁻ in (Na₂S) (gains 2 electrons). "oxidizing agent".
Alright, so that means we have 0.68 mol of the compound
For each 1 mol of the compound, we have 4*1 oxygens (because there are four oxygens in the formula)
Therefore for each 0.68 mol of the compound, we have 4*0.68 moles of oxygen!
One can tell by looking at the titration curve of an acid and base whether the acid used is a strong acid or a weak acid. For a titration of a strong acid and a strong base, the pH at the equivalence point will be neutral, that is, pH 7. If the titration involves a weak acid and a strong base, the pH at the equivalence point will not be neutral, the solution will be basic at the equivalence point.
It's observation and a hypothesis.
2.15 subtract by 1.86 then add 1.35 I think ...