CBSE Class 10 Science 2019 Delhi Set 1

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Question : 6
Total: 28
2g of silver chloride is taken in a china dish and the china dish is placed in sunlight for sometime. What will be your observation in this case? Write the chemical reaction involved in the form of a balanced chemical equation. Identify the type of chemical reaction.
OR
Identify the type of reactions taking place in each of the following cases and write the balanced chemical equation for the reactions.
(a) Zinc reacts with silver nitrate to produce zinc nitrate and silver.
(b) Potassium iodide reacts with lead nitrate to produce potassium nitrate and lead iodide.
Solution:  
2AgCl
Sunlight
2
Ag
+Cl2

Initially the colour of silver chloride is white but when it is kept in sunlight it breaks down to give silver and chlorine. Hence, the colour changes to grey.
It is an example of photo chemical decomposition.
2AgCl
Sunlight
2
Ag
+Cl2

OR
(a) The given reaction is a displacement reaction.
Zn
(s)
+
2AgNO3
(aq)
Zn(NO3)2
(aq.)
+
2Ag
(s)

(b) It is a double displacement reaction.
2KI
(\aq.)
+
Pb(NO3)2
(aq.)
2KNO3
(aq.)
+
PbI2
(s)
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