✓ Board-verified
Science · 2026 · 3 marks
CBSE 2026 · Region 4 · Set 2 · Q26
Answer the following: (a) Identify the substance oxidized and the substance reduced in the following reaction: 4 Na + O_2 → 2 Na_2 O (b) What type of…
Answer the following :
(a)
Identify the substance oxidized and the substance reduced in the following reaction : \[4 \mathrm{Na}+\mathrm{O}_{2} \longrightarrow 2 \mathrm{Na}_{2} \mathrm{O} \]
(b)
What type of reaction occurs when Lead (II) nitrate solution is mixed with potassium iodide solution ?
(c)
Why is silver chloride stored in dark coloured bottles ?
Marking-scheme solution
Substance oxidised = Na
Substance reduced = \(\displaystyle \mathrm{O}_{2}\)
(b) Double displacement/Precipitation reaction
(c) Silver chloride decomposes into silver and chlorine by sunlight.
All Chemical Reactions and Equations questions2026 question paperNCERT solutions: Chemical Reactions and EquationsPractice Chemical Reactions and Equations →
More from Chemical Reactions and Equations
- Copper powder is taken in a china dish and heated over a burner. Name the product formed and state its colour. Write the chemical equation for the…2024
- Why do we balance a chemical equation? Name and state the law that suggests the balancing of a chemical equation? Balance the following chemical…2025
- Zn+2 CH_3 COOH →(CH_3 COO)_2 Zn+H_2 The above reaction is a:2024
- Which of the following is not a thermal decomposition reaction?2024
- 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_3 → 2 KCl+3 O_22025
- Which of the following is an example of a displacement reaction?2026
- Define a double displacement reaction. Write the chemical equation of a double displacement reaction which is also a (i) Neutralization reaction and…2023
- Answer the following questions in the context of electrolysis of water: Why is this reaction/process called a decomposition reaction? Giving reason…2024
CBSE Class 10 Science past-paper question from the 2026 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.