CBSE Class 10 Science 2023 Delhi Set 1

Question : 21 of 39

Marks: +1, -0

(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.
OR
(B) The industial 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}

Solution:

(A) (i) The compound is copper (II) chloride

( {\CuCl}_2)

and it is bluish in colour.
(ii)

{\CuO} (s) +2 {\HCl} (aq) → {\CuCl}_2 (aq) + {\H}_2 {\O}(l)

OR
(B)

\; {\X}= {\NaCl} \;\text " (Sodium chloride); "\;

\; {\Y}= {\H}_2 \;\text " (Hydrogen gas); "\;

\; {\Z}= {\Cl}_2 \;\text " (Chlorine gas); "\;

\; {\B}= {\Bleaching} \;\text " powder "\; ( {\CaOCl}_2) .

\;2 {\NaCl}( {\aq})+2 {\H}_2 {\O}( {\l}) → 2 {\NaOH}_{( {\aq})} \;\; + {\Cl}_2( {\g})+ {\H}_2( {\g})

\; \;\; {\Ca}( {\OH})_2+ {\Cl}_2 → {\CaOCl}_2+ {\H}_2 {\O}

Go to Question:

Prev Question

Next Question