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Science · 2024 · 3 marks
CBSE 2024 · Region 3 · Set 2 · Q27
(a)State giving reason the reduction process to obtain the following metals from their compounds :(i)Mercury,(ii)Copper and(iii)SodiumOR 27. (b) State giving reason for the change in appearance observed when each of the following metal is exposed to atmospheric air for some time :(i)Silver,(ii)Copper and(iii)Iron
(a)
State giving reason the reduction process to obtain the following metals from their compounds :
(i)
Mercury,
(ii)
Copper and
(iii)
Sodium
OR 27. (b) State giving reason for the change in appearance observed when each of the following metal is exposed to atmospheric air for some time :
(i)
Silver,
(ii)
Copper and
(iii)
Iron
Marking-scheme solution
(i) Reduction Process- Roasting Reason- Mercury has low reactivity.
(ii) Reduction Process- Roasting Reason- Copper has low reactivity.
(iii) Reduction Process- Electrolytic Reduction. Reason- Sodium has high reactivity OR
(b)
(i) Change in appearance - White to black colour. Reason- Silver sulphide is formed.
(ii) Change in appearance - Reddish brown to green colour. Reason- Basic Copper Carbonate is formed.
(iii) Change in appearance- Grey to brown colour. Reason- Rust (iron oxide) is formed.
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CBSE Class 10 Science past-paper question from the 2024board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.