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Important Questions

CBSE Guess > Papers > Important Questions > Class XII > 2010 > Chemistry > Chemistry By Ms. Mohini Belani

CBSE CLASS XII

Q. 1. Chlorine , bromine and iodine show variable oxidation states.

Q. 2. Halogens act as good oxidizing agents.

Q. 3. Fluorine cannot be prepared from fluorides by chemical oxidation.

Q. 4. When blue litmus is dipped into a solution of hypochlorous acid, it first turns red and later gets decolorized.

Q. 5. Fluorine is a nonmetal while iodine shows some metallic properties as well.

Q. 6. A fresh iodine stain can be removed by washing with hypo.

Q. 7. Dry chlorine does not bleach clothes.

Q. 8. Ferric iodide is very unstable but ferric chloride is stable.

Q. 9. HF has a greater electronegativity difference and more ionic character than HCl, HBr and HI but it is the weakest acid.

Q. 10. An aqueous solution of iodine becomes colourless on adding excess of sodium hydroxide solution.

Q. 11. Bleaching powder loses its bleaching property when kept in an open bottle for long time.

Q. 12. Pure HI kept in a bottle acquires a brown colour after sometime.

Q. 13. Iodine dissolves more in KI solution than in water.

Q. 14. Fluorine does not form any oxyacid.

Q. 15. Fluorine gives fumes in moist air.

Q. 16. Colour of potassium iodide solution containing starch turns blue when chlorine water is added.

Q. 17. The brown colour of an acidified dilute solution of iodine in aqueous potassium iodide is intensified by addition of a nitrite but is discharged by the addition of sulphite.

Q. 18. HF is least volatile while HCl is most volatile amongst hydrogen halides.

Q. 19. Fluorine does not form polyhalide ion (F3-).

Q. 20. Anhydrous HCl is a bad conductor of electricity while aqueous HCl is a good conductor.

Q. 21. HF has a much higher boiling point than HCl.

Q. 22. Fluorine never acts as a central atom in its compounds with other halogens.

Q. 23. Perchloric acid is a stronger acid than sulphuric acid.

Q. 24. HF is a weaker acid than HCl in aqueous solution.

Q. 25. Addition of Cl2 to KI solution gives it a brown colour, but excess of Cl2 turns it colourless.

Q. 26. Bleaching of flowers by Cl2 is permanent, while that by SO2 is temporary.

Q. 27. The bond energy of F2 is less than that of Cl2.

Q. 28. Fluorine is a stronger oxidising agent than chlorine.

Q. 29. ClF3 exists but FCl3 does not.

Q. 30. NO2 readily forms a dimmer, whereas ClO2 does not.

Q. 31. The negative value of electron gain enthalpy of fluorine is less than that of chlorine.

Paper By Ms. Mohini Belani
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