# Question e0b9c

Feb 5, 2016

Reactions $\text{(i)}$ and $\text{(ii)}$.

#### Explanation:

I admit that I've never come across reactions $\text{(iii)}$ and $\left(\text{iv}\right)$, so right from the start I eliminated those two as possible valid answers.

Now, the first reaction will indeed produce carbon monoxide, $\text{CO}$.

When heated with concentrated sulfuric acid, potassium ferrocianide, "K"_4"Fe"("CN")_6, will produce

• potassium sulfate, ${\text{K"_2"SO}}_{4}$
• iron(II) sulfate, ${\text{FeSO}}_{4}$
• ammonium sulfate, ("NH"_4)_2"SO"_4
• carbon monoxide, $\text{CO}$

The balanced chemical equation for this reaction looks like this

${\text{K"_4"Fe"("CN")_text(6(aq]) + 6"H"_2"SO"_text(4(aq]) + 6"H"_2"O"_text((l]) -> 2"K"_2"SO"_text(4(aq]) + "FeSO"_text(4(aq]) + 3("NH"_4)_2"SO"_text(4(aq]) + 6"CO}}_{\textrm{\left(g\right]}} \uparrow$

Now, I assume that the second reaction is actually the decomposition of nickel tetracarbonyl, "Ni"("CO")_4#, since no other reactants are given.

Upon heating, nickel tetracarbonyl will decompose to form nickel metal and carbon monoxide. The balanced chemical equation for this reaction looks like this

${\text{Ni"("CO")_text(4(g]) stackrel(color(red)(Delta)color(white)(aa))(->) "Ni"_text((s]) + 4"CO}}_{\textrm{\left(g\right]}}$

This reaction is part of the Mond process, a technique used to extract nickel from impure nickel.

As far as the other two reactions go, I really don't see what could be going on there.

The only way I can think off to getting carbon monoxide from a zinc compound is by heating zinc oxide, $\text{ZnO}$, with carbon. The reaction will produce carbon monoxide and zinc vapor

${\text{ZnO"_text((s]) + "C"_text((s]) stackrel(color(red)(Delta)color(white)(aa))(->) "Zn"_text((g]) + "CO}}_{\textrm{\left(g\right]}}$

I assume that the last reaction involves heating magnesium carbonate with zinc metal. I don't think that adding zinc in there could change the fact that magnesium carbonate decomposes to form magnesium oxide, $\text{MgO}$, and carbon dioxide, ${\text{CO}}_{2}$.