Question Identification (First 30 seconds)

Numerical questions: Identify given quantities. If $n$, $R$, $T$, $V_1$, $V_2$ are given → work formula. If $\Delta H$ and $\Delta S$ are given → Gibbs equation. If $\Delta H_f^\circ$ values are given → Hess's Law.

Conceptual questions: Look for keywords: "equilibrium" → $\Delta G = 0$; "spontaneous at all temperatures" → $\Delta H < 0$, $\Delta S > 0$; "state function" → $U$, $H$, $S$, $G$ (not $q$ or $w$).

Assertion-Reason questions: Check each statement independently first. The most common A-R trap is "A true, R false" when R says "$\Delta G^\circ = 0$ at equilibrium."

Time Allocation

• Simple definition/concept MCQ: 30-45 seconds
• Calculation involving single formula: 60-90 seconds
• Multi-step calculation (bond enthalpy + Gibbs): 2-3 minutes
• Assertion-Reason: 60-90 seconds (evaluate both statements independently)

Common 1-Mark Saves

• "Which is not a state function?" → answer: q or w (both are path functions)
• "Spontaneous at all temperatures?" → answer: $\Delta H < 0$, $\Delta S > 0$
• "At equilibrium, which is true?" → answer: $\Delta G = 0$ (not $\Delta G^\circ = 0$)
• "Bond dissociation enthalpy is always?" → answer: positive
• "Enthalpy of combustion is always?" → answer: negative

Formula Priority Order for NEET

1. $\Delta G = \Delta H - T\Delta S$ (most tested)
2. $\Delta H = \Delta U + \Delta n_g RT$ (second most tested)
3. $w = -nRT\ln(V_2/V_1)$ (numerical)
4. $\Delta G^\circ = -RT\ln K$ (equilibrium link)
5. $C_p - C_v = R$ (heat capacity)