Chemical Reactions and Equations

CBSE Class 10 Science · every board question from this chapter, 2025–2025 · 14 of them repeated across years

• Example of thermal decomposition reaction are (i) 2 AgCl → 2 Ag+Cl 2 (ii) CaCO 3 → CaO+CO 2 (iii) 2 H 2 O → 2 H 2+O 2 (iv) 2 KClO…2025
• The main observations while performing the experiment of burning magnesium ribbon in air are: (i) Magnesium ribbon burns with a…2025asked 3×
• In which one of the following situations a chemical reaction does not occur?2025asked 3×
• Electrolysis of water is a decomposition reaction. The mass ratio (M H: M O) of hydrogen and oxygen gases liberated at the…2025asked 3×
• Consider the following chemical equation: pAl+q H 2 O → rAl 2 O 3+s H 2 To balance this chemical equation, the values of 'p',…2025asked 3×
• Select from the following a statement which is not true about burning of magnesium ribbon in air:2025asked 2×
• The colour of the solution observed after about 1 hour of placing iron nails in copper sulphate solution is2025asked 3×
• When a mixture of baking soda and tartaric acid is heated (or mixed in water) a product 'X' is formed, which is responsible for…2025
• The values of a, b, c and d in the following balanced chemical equation are respectively: a Pb(NO 3) 2 heat b PbO+c NO 2+d O 22025asked 3×
• Assertion: All exothermic reactions are accompanied with evolution of heat and light. Reason (R): Combination reactions may or…2025
• Assertion: Silver chloride turns grey in sunlight. Reason (R): Decomposition of silver chloride into silver and chlorine takes…2025asked 3×
• Assertion: Decomposition reactions are generally endothermic reactions. Reason (R): Decomposition of organic matter into compost…2025asked 3×
• While burning a magnesium ribbon in air, list two safety measures which should be followed. Also state two observations of this…2025
• Name the compound used in black and white photography. State whether the reaction that occurs is exothermic or endothermic. Give…2025
• Balance the following chemical equations: CO 2+H 2 O [ Chlorophyll ] Sunlight C 6 H 12 O 6+O 2+H 2 O Pb(NO 3) 2 Heat PbO+NO 2+O 22025
• A student performs the following experiment in his school laboratory. List two observations to justify that in this experiment a…2025asked 2×
• Define oxidation. Identify and name the substance oxidised in the following reaction: CuO+H 2 → Cu+H 2 O2025
• List the possible sources of energy required in decomposition reactions. Illustrate any one with a suitable example. OR What is…2025asked 3×
• A copper wire on burning in flame, gets coated with a black substance. Write the chemical equation of the reaction that takes…2025
• What happens when: (write balanced chemical equation) Lead nitrate is thermally decomposed, Natural gas burns in oxygen (or air)?2025
• Translate the following statements into chemical equations and then balance them: Nitric acid reacts with calcium hydroxide to…2025
• Write chemical equation for the chemical reaction between the aqueous solutions of sodium sulphate and barium chloride. State two…2025
• Why do we balance a chemical equation? Name and state the law that suggests the balancing of a chemical equation? Balance the…2025asked 3×
• State the change that is observed when a China dish containing copper powder is heated over the flame of a burner. Name the…2025
• Write balanced chemical equation for the reactions that occur when steam is passed over red hot iron. natural gas is burnt in…2025asked 2×
• How is a double displacement reaction different from a displacement reaction? Explain giving example in the form of balanced…2025
• (i) Define the term decomposition reaction. Write one chemical equation each for decomposition reaction where energy is supplied…2025asked 3×

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