Chapter Exam

Chapter 2: Chemical Equations — Online MCQ Test

Q: Which of the following represents the state symbol for a gaseous substance?

Answer: C. (g) — (g) denotes the gaseous state; (s) is solid, (l) is liquid, and (aq) is aqueous solution.

Q: Identify the reactants and products in the equation: 2Na + Cl₂ → 2NaCl

Answer: A. Reactants: Na and Cl₂; Products: NaCl — Reactants are the substances on the left side of the arrow (Na and Cl₂), and products are the substances on the right side (NaCl).

Q: In the balanced equation 2C + O₂ → 2CO, how many grams of O₂ are needed to completely react with 6 grams of C? (Atomic mass: C = 12, O = 16)

Answer: A. 8 grams — Moles of C = 6/12 = 0.5 mol. From the equation, 2 mol C requires 1 mol O₂. So 0.5 mol C requires 0.25 mol O₂ = 0.25 × 32 = 8 grams.

Q: Consider the equation 2KMnO₄ + 16HCl(conc.) → 2KCl + 2MnCl₂ + 5Cl₂ + 8H₂O. Which element undergoes both oxidation and reduction simultaneously?

Answer: C. Chlorine (Cl) — Chlorine in HCl is oxidized to Cl₂ (0 oxidation state) while some Cl⁻ forms MnCl₂ remaining as -1. Chlorine exhibits both oxidation and reduction—a disproportionation reaction.

PHYSICAL SCIENCES · CLASS 10th · Telangana State Board

Practice Chapter 2: Chemical Equations with a free chapter-wise online MCQ test for Telangana State Board CLASS 10th PHYSICAL SCIENCES. This chapter covers: This foundational chemistry chapter covers how chemical transformations are represented using formulas and balanced equations. Students learn to write state symbols identify reacta.... AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 2: Chemical Equations — Important Questions & Answers (FAQ)

Frequently asked questions from Telangana State Board CLASS 10th PHYSICAL SCIENCES — Chapter 2: Chemical Equations, with answers and explanations. These are sample questions; the exam has its own separate question set.

What is a chemical equation?

A. A symbolic representation of a chemical reaction using formulas and coefficients ✓
B. A mathematical equation used to calculate the mass of reactants
C. A statement describing the properties of chemical substances
D. A diagram showing the arrangement of atoms in molecules

Answer: A. A symbolic representation of a chemical reaction using formulas and coefficients
A chemical equation uses chemical formulas and coefficients to represent how reactants transform into products during a chemical reaction.

Which of the following represents the state symbol for a gaseous substance?

A. (s)
B. (l)
C. (g) ✓
D. (aq)

Answer: C. (g)
(g) denotes the gaseous state; (s) is solid, (l) is liquid, and (aq) is aqueous solution.

Identify the reactants and products in the equation: 2Na + Cl₂ → 2NaCl

A. Reactants: Na and Cl₂; Products: NaCl ✓
B. Reactants: NaCl; Products: Na and Cl₂
C. Reactants: 2Na; Products: 2NaCl and Cl₂
D. Reactants: Na and NaCl; Products: Cl₂

Answer: A. Reactants: Na and Cl₂; Products: NaCl
Reactants are the substances on the left side of the arrow (Na and Cl₂), and products are the substances on the right side (NaCl).

In the balanced equation 2C + O₂ → 2CO, how many grams of O₂ are needed to completely react with 6 grams of C? (Atomic mass: C = 12, O = 16)

A. 8 grams ✓
B. 16 grams
C. 32 grams
D. 12 grams

Answer: A. 8 grams
Moles of C = 6/12 = 0.5 mol. From the equation, 2 mol C requires 1 mol O₂. So 0.5 mol C requires 0.25 mol O₂ = 0.25 × 32 = 8 grams.

Consider the equation 2KMnO₄ + 16HCl(conc.) → 2KCl + 2MnCl₂ + 5Cl₂ + 8H₂O. Which element undergoes both oxidation and reduction simultaneously?

A. Potassium (K)
B. Manganese (Mn)
C. Chlorine (Cl) ✓
D. Hydrogen (H)

Answer: C. Chlorine (Cl)
Chlorine in HCl is oxidized to Cl₂ (0 oxidation state) while some Cl⁻ forms MnCl₂ remaining as -1. Chlorine exhibits both oxidation and reduction—a disproportionation reaction.