Chemistry — Prelims Strategy

Prelims Strategy

Read a reaction question by inventorying atoms before naming the reaction. If an option balances an equation by altering a compound's formula, it changes the problem. Next identify the role of each substance: what loses oxygen or electrons, what gains them, and which reactant acts as the agent. Role reversal is a more plausible trap than an unrelated chemical name.

For conductivity, ask which charged particles are free to move in the stated physical condition. A salt crystal, molten salt and salt solution cannot be treated as equivalent merely because they share a chemical formula. For displacement, use the relative reactivity relevant to the given pair; the presence of a metal alone does not guarantee reaction.

Practise explaining each rejected option in one sentence before consulting the key. A useful incorrect option may describe a real process under different conditions, such as electronic conduction in a metal. That makes the condition in the stem decisive. Record the confusion that produced an error, rather than memorising the position of the correct option.