9.1.7 Oxidation and Reduction in Term of Change of Oxidation Number (MCQ)

The equation represents the redox reaction between ammonia and copper(II) oxide.

2NH₃ + 3CuO → N₂ + 3Cu + 3H₂O

Which of the following is true about the reaction?

The oxidation number of calcium increases when

Which of the underlined substances in the following equations undergo oxidation?

Which of the following statements about a chemical reaction are true?

A substance undergoes oxidation if

Which of the following indicates that a substance undergoes reduction?

Which of the following is NOT true about oxidation and reduction?

Which of the underlined substances in the following equations undergo oxidation?

The half equation represents the reduction reaction of acidified potassium dichromate(VI) solution.
\[
\mathrm{Cr}_2 \mathrm{O}_7^{2-}+\mathrm{xH}^{+}+\mathrm{ye}^{-} \longrightarrow \mathrm{zCr}^{3+}+7 \mathrm{H}_2 \mathrm{O}
\]
What are the value of \(x, y\) and \(z\) ? 

\begin{align}
\begin{array}{|c|c|c|c|}
\hline & x & y & z \\
\hline \text { A } & 14 & 6 & 2 \\
\hline \text { B } & 14 & 5 & 1 \\
\hline \text { C } & 7 & 2 & 1 \\
\hline \text { D } & 7 & 1 & 2 \\
\hline
\end{array}
\end{align}