Which of the following catalysts is used in the hydrogenation of alkenes? MCQ with Answer and Explanation

Explanation:
Nitrogen has 5 valence electrons; it needs 3 more to complete the octet. It shares three electrons with three hydrogen atoms, forming three covalent bonds. Therefore, valency is 3. In the case of nitrogen, covalency is 3, while its electrovalency could be 5 (losing all 5). For covalent molecules, valency = number of shared electron pairs. In N₂, valency is also 3 (triple bond).

Explanation:
Alkenes contain at least one carbon-carbon double bond. The simplest alkene is ethene (C₂H₄). Methane is an alkane; ethane is an alkane; propyne is an alkyne. General formula for alkenes: CₙH₂ₙ.

Explanation:
Hydrogen peroxide is a strong oxidizing agent. In dilute solutions (3-6%), it is used as a mild antiseptic for minor cuts and as a bleaching agent for hair, teeth, and delicate materials like silk and wool. It decomposes into water and oxygen.