Exams › JEE Main › Chemistry

For the reaction A(g) + 2B(g) <=> C(g), the equilibrium constant is Kc = 0.25 dm⁶ mol⁻². In a 5 dm³ vessel, how many moles of A must be combined with 4 mol of B so that 1 mol of C is present at equilibrium?

1. 3 moles
2. 24 moles
3. 26 moles
4. None of these

Correct answer: 26 moles

Solution

At equilibrium B = 4 - 2 = 2 mol, C = 1 mol, A = (a-1) mol. Converting to molarity (divide by 5) and using Kc = 0.25 gives a-1 = 25, so a = 26 mol.

Related JEE Main Chemistry questions

• The solubility product constants of Ag2CrO4, AgCl, AgBr and AgI are 1.1 × 10⁻¹², 1.8 × 10⁻¹⁰, 5.0 × 10⁻¹³ and 8.3 × 10⁻¹⁷, respectively. If AgNO3 solution is added to a mixture containing equal amounts of NaCl, NaBr, NaI and Na2CrO4, which silver salt will begin to precipitate at the highest Ag+ concentration, i.e., the last one to form?
• Two sparingly soluble salts, MY and NY3, each have the same solubility product constant, Ksp = 6.2 × 10⁻¹³, at room temperature. Which of the following statements is correct for these two salts?
• Given the equilibrium constants for these reactions: N2 + 3H2 ⇌ 2NH3, K1 N2 + O2 ⇌ 2NO, K2 H2 + 1/2 O2 ⇌ H2O, K3 What is the equilibrium constant K for the reaction 2NH3 + 5/2 O2 ⇌ 2NO + 3H2O ?
• In a saturated solution of Ag2C2O4, the concentration of Ag+ ions is 2.2 × 10⁻⁴ mol L⁻¹. The solubility product constant (Ksp) of Ag2C2O4 is:
• For the gaseous equilibrium PCl₅ ⇌ PCl₃ + Cl₂, how does the degree of dissociation (α) depend on the equilibrium pressure (p)?
• A movable-piston vessel of volume 20 L at 400 K contains CO₂(g) at a pressure of 0.4 atm along with excess SrO (ignore the solid’s volume). The piston is pushed inward, reducing the container volume. What is the largest volume the vessel can have when the CO₂ pressure reaches its highest value? Given: SrCO₃(s) ⇌ SrO(s) + CO₂(g), Kp = 1.6 atm

⚔️ Practice JEE Main Chemistry free + battle 1v1 →