Chemical Equations and Reactions

• Zn

• H

• S

• O

Tags

NGSS.HS-PS1-1

Which of the following equations represents a decomposition reaction?

Answer explanation

Decomposition reactions have the general form AB --> A + B

• double displacement reaction

• synthesis reaction

• decomposition reaction

• combustion reaction

Answer explanation

Double displacement reactions have the general form: AB + CD --> AD + CB

• double displacement reaction

• synthesis reaction

• decomposition reaction

• combustion reaction

Answer explanation

Combustion reactions are typically some fuel + O2 gas. When the fuel contains only C, H (and possibly O), the products are CO2 and H2O. This makes these reactions easy to identify.

Which of the following statements about the given reaction are correct? 3Fe(s) + 4H2O(g) ® Fe3O4(s) + 4H2(g) (i) Iron metal is getting oxidised (ii) Water is getting reduced (iii) Water is acting as reducing agent (iv) Water is acting as oxidising agent

• (a) (i), (ii) and (iii)

• (b) (iii) and (iv)

• (c) (i), (ii) and (iv)

• (d) (ii) and (iv)

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of the following are combination reactions?

• (a) (i) and (iii)

• (b) (iii) and (iv)

• (c) (ii) and (iv)

• (d) (ii) and (iii)

Barium chloride on reacting with ammonium sulphate forms barium sulphate and ammonium chloride. Which of the following correctly represents the type of the reaction involved?

• (i) Displacement reaction

• (ii) Precipitation reaction

• (iii) Combination reaction

• (iv) Double displacement reaction

Which among the following is(are) double displacement reaction(s)? (i) Pb + CuCl₂ --> PbCl₂ + Cu (ii) Na₂SO₄ + BaCl₂ --> BaSO₄ + 2NaCl (iii) C + O₂ --> CO₂ (iv) CH₄ + 2O₂ --> CO₂ + 2H₂O

• (a) (i) and (iv)

• (b) (ii) only

• (c) (i) and (ii)

• (d) (iii) and (iv)

The following reaction is used for the preparation of oxygen gas in the laboratory 2KClO₃ (s) + Heat --Catalyst--> 2KCl (s) + 3O₂ (g) Which of the following statement(s) is(are) correct about the reaction?

• (a) It is a decomposition reaction and endothermic in nature

• (b) It is a combination reaction

• (c) It is a decomposition reaction and accompanied by release of heat

• (d) It is a photochemical decomposition reaction and exothermic in nature

Tags

NGSS.HS-PS1-4

Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is

• (a) 1:1

• (b) 2:1

• (c) 4:1

• (d) 1:2

Tags

NGSS.HS-PS1-7