Class 10 Science

Piyush365

Asked: September 30, 2025In: Class 10 Science

During a laboratory experiment, a student compared the reactivity of aluminium, sodium and lead with dilute hydrochloric acid. He added small pieces of each metal into separate test tube containing HCl and observed: • Aluminium caused the solution to heat up. • Sodium reacted vigorously with flames. • Lead produced Bubbles slowly. (a) Explain the reason for the rise in temperature when aluminium reacts with dilute HCl. (b) Give a reason why the reaction of sodium with dilute HCl is extremely vigorous. (c) State why the reaction of lead with dilute HCl is slow and produces only a few bubbles.

(a) Aluminium reacts with dilute HCl in an exothermic reaction, releasing heat and hydrogen gas, causing the temperature to rise. (b) Sodium reacts vigorously with HCl due to its high reactivity, producing hydrogen gas rapidly with heat. (c) Lead reacts ...

Piyush365

Asked: September 30, 2025In: Class 10 Science

Write chemical equation to show what happens when ethanol: (I) burns in oxygen/air. (II) is heated at 443 K in excess conc. sulphuric acid. (III) reacts with acidified potassium dichromate.

(I) Combustion: C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O (II) Dehydration: C₂H₅OH →[conc. H₂SO₄, 443 K] C₂H₄ + H₂O (III) Oxidation: C₂H₅OH + [O] → CH₃CHO + H₂O (using acidified K₂Cr₂O₇) CBSE Sample Paper Class 10 Science 2025-26 Tiwari Academy provides CBSE Class 10 ...

Piyush365

Asked: September 30, 2025In: Class 10 Science

A carbon compound X is a good solvent. On reaction with sodium, X forms two products Y and Z. Z is used to convert vegetable oil into vegetable ghee. Identify and name X, Y and Z. Also write the equation of reaction of X with sodium to justify your answer.

X: Alcohol (ethanol, C₂H₅OH) – a good solventY: Hydrogen gas (H₂)Z: Sodium ethoxide (C₂H₅ONa) – used in making vegetable ghee Reaction: 2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂↑ 10 years solved cbse sample paper for class 10 science 2026 board exam ...

Piyush365

Asked: September 30, 2025In: Class 10 Science

A student performs the following experiment in his school laboratory. List two observations to justify that in this experiment a chemical change has taken place.

Two observations that indicate a chemical change are: (1) Formation of a new substance, such as a gas, precipitate, or color change. (2) Release or absorption of energy, like heat, light, or sound, during the reaction. 2025-26 sample paper question available ...

Poll

Piyush365

Asked: September 30, 2025In: Class 10 Science

Assertion (A): Baking soda is used in soda-acid fire extinguisher. Reason (R): On heating, it releases carbon dioxide which helps extinguish fire.

Both A and B are true but R is not the correct explanation of A. Baking soda is used in Soda acid fire extinguishers because it release is carbon dioxide gas upon reaction with H2SO4. CO2 helps put out fire ...

Category: Class 10 Science

Write chemical equation to show what happens when ethanol: (I) burns in oxygen/air. (II) is heated at 443 K in excess conc. sulphuric acid. (III) reacts with acidified potassium dichromate.

A carbon compound X is a good solvent. On reaction with sodium, X forms two products Y and Z. Z is used to convert vegetable oil into vegetable ghee. Identify and name X, Y and Z. Also write the equation of reaction of X with sodium to justify your answer.

A student performs the following experiment in his school laboratory. List two observations to justify that in this experiment a chemical change has taken place.

Assertion (A): Baking soda is used in soda-acid fire extinguisher. Reason (R): On heating, it releases carbon dioxide which helps extinguish fire.

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