Page 88 - Chemistry - XI

Q9. Why is yellowish brown layer formed in CCl in chlorine water test?
4
Ans. lt is because bromine dissolves in CCl which is displaced by chlorine.
Cl + 2KBr → 2KCl + Br 4
2 2
Q10. Why is violet layer formed in chlorine water test?
Ans. It is because to iodine dissolves in CCl or CHCl . Chlorine displaces iodine.
Cl + 2NaI → 2NaCl + I 4 3
2 2
Q11. Why does AgCl dissolve in excess of NH OH?
4
Ans. It is due to the formation of [Ag(NH ) ] Cl .
+
–
3 2
Q12. Why do we get white precipitate with AgNO in the test for chlorine?
Ans. It is due to the formation of AgCl. 3

Q13. Why does blue colour appear in the test for nitrogen?
Ans. It is due to the formation of ferric ferrocyanide.
Q14. Why is sodium metal kept under kerosene oil?
Ans. It is kept under kerosene oil because sodium is highly reactive and catches fi re in presence of
moisture.

Q15. Why is sodium extract alkaline?
Ans. Unreacted metallic sodium reacts with H O to form metal hydroxide and hydrogen gas.
2

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