Internal means inside and external means outside
I think the correct answer would be C. The common characteristic that is shareed by the elements found at the center of a period would be that they are the least reactive species. Having lower value of electronegativity, there is less ionization of the atoms which would also contribute to less reactivity.
The atom that is oxidized : Cr
The oxidizing agent : H₃PO₄
<h3>Further explanation</h3>
Reaction
2 H₃PO₄ (aq) + 2Cr(s) → 2 CrPO₄ (aq) + 3H₂(g)
Atoms undergoing a reduction reaction (decrease in oxidation number) and an oxidation reaction (increase in oxidation number)
H⁺(in H₃PO₄) =+1
H₂=0
Cr = 0
Cr³⁺(in CrPO₄ )
the oxidizing agent.⇒which undergoes a reduction reaction and oxidizes another compound/element : H₃PO₄
The correct answer is: by the transfer of one or more electrons from one atom to another.
Answer: The concentration of the acid is 0.01 moles acid/0.040 L = 0.25 moles/L = 0.25 M
Explanation: