English Medium Class 10 - CBSE Question Bank Solutions for Science

Name the gas evolved when dilute HCl reacts with sodium hydrogencarbonate. How is it recognised?

Give the names and formulae of two strong acids.

Name one natural source of the following acid:

Citric acid

Name one natural source of the following acid:

Oxalic acid

Name one natural source of the following acid:

Tartaric acid

Name one animal whose stings contain formic acid (or methanoic acid).

What is a chemical equation? Explain with the help of an example.

Giving examples, state the difference between balanced and unbalanced chemical equations.

Balance the following chemical equation:

\[\ce{NH3 -> N2 + H2}\]

Balance the following chemical equation:

\[\ce{C + CO2 -> CO}\]

When hydrogen is passed over copper oxide, copper and steam are formed. Write a balanced equation for this reaction and state which of the chemicals are:

1. elements
2. compounds
3. reactants
4. products
5. metal
6. non-metal

What are the various ways in which a chemical equation can be made more informative? Give examples to illustrate your answer.

Write a balanced chemical equation from the following information:

An aqueous calcium hydroxide solution (lime water) reacts with carbon dioxide gas to produce a solid calcium carbonate precipitate and water.

Aluminium burns in chlorine to form aluminium chloride (AlCl₃). Write a balanced chemical equation for this reaction.

Explain, with an example, how the physical states of the reactants and products can be shown in a chemical equation.

Balance the following equation and add state symbols:

\[\ce{Zn + HCl -> ZnCl2 + H2}\]

Convey the following information in the form of a balanced chemical equation:

“An aqueous solution of ferrous sulphate reacts with an aqueous solution of sodium hydroxide to form a precipitate of ferrous hydroxide and sodium sulphate remains in solution.”

Name the acid-base indicator extracted from lichen.

What colour does the turmeric paper turn when put in an alkaline solution?

Write any two observations in an activity which may suggest that a chemical reaction has taken place. Give an example in support of your answer.