Which of the following molecules has a linear shape? MCQ with Answer and Explanation

Explanation:
Allotropes are different structural forms of the same element. Diamond has a tetrahedral sp³ network, while graphite has a planar sp² layered structure. This difference in atomic arrangement results in distinct physical properties: diamond is hard, transparent, insulating; graphite is soft, black, conducting. Allotropes have same chemical composition (pure carbon). Other allotropes include fullerenes and graphene.

Explanation:
Urea (CO(NH₂)₂) is a nitrogenous fertilizer with the highest nitrogen content (about 46%). Superphosphate provides phosphorus, muriate of potash (KCl) provides potassium, and gypsum (CaSO₄·2H₂O) is a soil conditioner providing calcium and sulfur, not primary NPK nutrients.

Explanation:
James Chadwick discovered the neutron in 1932. It is a neutral particle with mass almost equal to proton. Its discovery explained isotopes' mass differences.