Which of the following is a mixed fertilizer? MCQ with Answer and Explanation

Explanation:
White phosphorus exists as P₄ tetrahedral molecules, containing 4 phosphorus atoms. So atomicity is 4. Sulfur is S₈, oxygen is O₂, ozone O₃. Atomicity is the number of atoms in a molecule of an element. Phosphorus is a non-metal. Red phosphorus is polymeric but P₄ is the common molecular form.

Explanation:
Methanol (CH₃OH) contains the hydroxyl (–OH) functional group characteristic of alcohols. It is the simplest alcohol, also called wood alcohol. Ethanol (C₂H₅OH) is the alcohol in beverages. Aldehydes have –CHO group, ketones have >C=O, carboxylic acids have –COOH. Methanol is toxic; ingestion can cause blindness or death. It is used as a solvent and in formaldehyde production.

Explanation:
To balance the equation: Fe atoms: 3 on right, so a=3. O atoms: 4 on right, so b=4. H atoms: 4*2=8 on left, so d=4. The balanced equation is 3Fe + 4H₂O → Fe₃O₄ + 4H₂. Thus, a=3, b=4, c=1, d=4. This ensures the law of conservation of mass is obeyed.