← Back to Chapter
Important:
CBSE's official archive provides complete Class 10 Science
examination papers. It does not reliably tag individual
questions chapter-wise on the archive page, so this page does
not falsely label unverified questions as a specific year's PYQ.
Official CBSE Previous Year Papers
Class 10 Science – 2026
Open the official CBSE question-paper archive and select
the Class 10 Science paper.
Open Official 2026 Paper →
Chapter-Focused Practice
Practice Question 1
A solution has pH 3 while another has pH 9. Compare their
acidic and basic nature.
The solution with pH 3 is acidic, while the solution with
pH 9 is basic. Lower pH indicates greater acidic character
and higher pH above 7 indicates basic character.
Practice Question 2
Write the balanced equation for the reaction of sodium
hydrogencarbonate with hydrochloric acid.
NaHCO₃ + HCl → NaCl + H₂O + CO₂
Practice Question 3
Explain why an aqueous solution of an acid conducts
electricity.
Acids produce ions in aqueous solution, and these ions carry
electric charge through the solution.
Practice Question 4
Why does carbon dioxide turn lime water milky?
Calcium carbonate is formed as an insoluble precipitate.
Ca(OH)₂ + CO₂ → CaCO₃ + H₂O
Practice Question 5
What happens when gypsum is heated to prepare Plaster of Paris?
Gypsum loses part of its water of crystallisation.
CaSO₄·2H₂O → CaSO₄·½H₂O + 1½H₂O
The product is Plaster of Paris.