Question

Recorded data:
Before$:$ $CuO+$porcelain boat$=62.869$g
$CaC{l}_2+$U-tube$=80.483$g
After:Porcelain boat$+$contents $=54.869$g
$CaC{l}_2+$U-tube$=89.483$g
Reactions:$Zn\left(s\right)+2HCl\left(aq\right)\to ZnC{l}_2\left(aq\right)+H_2\left(g\right)$ then $H_2\left(g\right)+CuO\left(s\right)\to H_{2}O\left(g\right)+Cu\left(s\right)$
What type of reaction occurred in the porcelain boat?

• A. Electrolysis
• B. Double displacement
• C. Reduction and oxidation
• D. Decomposition or analysis
• E. Combination or synthesis

Answer 1

The correct option is C Reduction and oxidation

Reduction and oxidation occurred in the porcelain boat.
$H_2\left(g\right)+CuO\left(s\right)\to H_{2}O\left(g\right)+Cu\left(s\right)$
$H_2$ gas (obtained from the reaction of $Zn$ with $HCl$) reduces cupric oxide to copper metal. The oxidation number of copper decreases from +2 to 0.
Hydrogen gas is oxidized to water. The oxidation number of hydrogen increases from 0 to +1.