Chapter 2: Chemical Equations — Online MCQ Test
PHYSICAL SCIENCES · CLASS 10th · Telangana State Board
Practice Chapter 2: Chemical Equations with a free chapter-wise online MCQ test.
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....
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Chapter 2: Chemical Equations — Important Questions & Answers
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.
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.
(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).
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.
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.
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.