Class 10 — Chemistry

Q1. A reaction that can go in both directions is called:

✔ Correct: B — Reversible reactions proceed forward and backward simultaneously.

Q2. At dynamic equilibrium, concentrations of reactants and products:

✔ Correct: C — Concentrations stay constant because forward and reverse rates are equal; they are not necessarily equal to each other.

Q3. The value of Kc depends on:

✔ Correct: C — Kc changes only with temperature.

Q4. In the Haber process, the catalyst used is:

✔ Correct: B — Finely divided iron is the catalyst in ammonia synthesis.

Q5. Removing a product from an equilibrium mixture shifts the equilibrium:

✔ Correct: B — The system replaces the removed product (Le Chatelier principle).

Q6. A very large value of Kc indicates:

✔ Correct: B — Large Kc means products dominate at equilibrium.

Q7. The optimum temperature for the Haber process is about:

✔ Correct: C — About 450 C is the compromise between yield and rate.

Q8. Equilibrium in a reversible reaction is established in a:

✔ Correct: B — A closed system prevents reactants/products from escaping.

Q9. Increasing temperature favours the reaction which is:

✔ Correct: B — Heat acts like a reactant in endothermic reactions.

Q10. For the reaction H2 + I2 (rev) 2HI, Kc is:

✔ Correct: A — Kc = products raised to coefficients divided by reactants raised to coefficients.