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Science · 2023 · 2 marks
CBSE 2023 · Region 4 · Set 1 · Q21
(A) A student took a small amount of copper oxide in a conical flask and added dilute hydrochloric acid to it with constant stirring. He observed a…
A student took a small amount of copper oxide in a conical flask and added dilute hydrochloric acid to it with constant stirring. He observed a change in colour of the solution.
(i)
Write the name of the compound formed and its colour.
(ii)
Write a balanced chemical equation for the reaction involved.
The industrial process used for the manufacture of caustic soda involves electrolysis of an aqueous solution of compound'X'. In this process, two gases'Y'and'Z'are liberated. 'Y'is liberated at cathode and'Z', which is liberated at anode, on treatment with dry slaked lime forms a compound'B'. Name X, Y, Z and B.
Marking-scheme solution
(A) (i) • Copper (II) chloride / Copper chloride / Cupric chloride / \(\displaystyle \mathrm{CuCl}_{2}\)
colour- blue-green.
(ii) \(\displaystyle \mathrm{CuO}+2 \mathrm{HCl} \rightarrow \mathrm{CuCl}_{2}+\mathrm{H}_{2} \mathrm{O}\)
(B) X : Sodium Chloride / NaCl
Y : Hydrogen \(\displaystyle / \mathrm{H}_{2}\)
Z : Chlorine \(\displaystyle / \mathrm{Cl}_{2}\)
B : Bleaching powder / \(\displaystyle \mathrm{CaOCl}_{2}\)
All Acids, Bases and Salts questions2023 question paperNCERT solutions: Acids, Bases and SaltsPractice Acids, Bases and Salts →
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CBSE Class 10 Science past-paper question from the 2023 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.