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FBISE Chemistry XII (2018-Second Group)

FBISE Chemistry XII (2018-Second Group)

1. Which is not correct order of stability of oxidation states of group IV A elements?





... Answer is d)
Explanation: Pb+2 is more stable than Pb+4. That is why PbCl4 is readily changed into PbCl4. In group IV elements, the stability order in +4 oxidation state decreases down the group while the stability order in +2 oxidation state increases down the group. Therefore above three option are correct.

2. The only akaline earth metal which reacts with alkalies is





... Answer is a)
Explanation: Be reacts with alkalies to form hydrogen gas and sodium bryllate Na2BeO2 while other alkaline earth metals donot react.

3. Coordination of zinc in complex ion [Zn(NH2-CH2-CH2-NH2)3]+2 is





... Answer is d)
Explanation: Coordination of zinc in complex ion [Zn(NH2-CH2-CH2-NH2)3]+2 is 6, because zinc is bonded with three bidentate ligands

4. Which one of the followings can be used to distinguish between Fe+2 and Fe+3





... Answer is d)
Explanation: On adding thiocyanate ions, SCN- in the form of sodium or potassium thiocyanate, to a solution containing Fe+3, intense red blood red solution containing [Fe(SCN)(H2O)5)]+2.

5. The reagent used to detect phosphorous present in organic compound





... Answer is b)
Explanation: When excess of ammonium molybdate is added to a solution containing phosphate ions, a yellow colouration indicates the the presence of phosphorous.

6. Geometrical isomerism is shown by





... Answer is d)
Explanation: Geometrical isomerism is shown by 2-butene. All alkenes donot show geometrical isomerism. Geometrical isomerism is possible with those alkene in which each double bonded carbon atom is attached with two different atoms or groups.

7. 2,3-Dimethyl-2-butene on reaction with O3/H2O gives





... Answer is a)
Explanation: 2,3-Dimethyl-2-butene on ozonolysis with O3 gives symmertrical ozonoid which upon hydrolysis with H2O gives acetaldehyde.

8. Which one of the following is poor leaving group in SN reactions?





... Answer is a)
Explanation: Strong bases are poor leaving group and vice versa. As F- is stron base due to highest charge density, so it is poor leaving group.

9. The more acidic compound among the following is





... Answer is a)
Explanation: CH3COOH is relatively stronger acid than other acids due to its relatively most stable acetate ion.

10. The alcohol with greater reactivity with respect to the cleavage of its C-O bond is





... Answer is d)
Explanation: On cleavage of C-O bond, carbocation is formed. So, reactivity of alcohol increases with increase in stability of carbocations. Therefore, Ter-alcohol is the most reactive and CH3OH is the least reactive.

11. The sarettee reagent is





... Answer is c)
Explanation: Sarattee reagent is complex of CrO3 bonded with two Pyridine rings.

12. An acetal is produced when acetaldehyde reacts with





... Answer is b)
Explanation: An acetal is formed when acetaldehyde reacts with an alcohol.

13. Acetamide can be prepared by heating





... Answer is b)
Explanation: Acetamide can be prepared by heating ammonium acetate.

14. Which one of the following is not present in RNA?





... Answer is d)
Explanation: In RNA, instead of Thymine, Uracil base is present

15. Which dye is used in boot polish





... Answer is d)
Explanation: Nail polish composed of Bismarck brown dye.

16. Peroxy Acetyl Nitrate (PAN) is the secondary pollutant which affects





... Answer is b)
Explanation: Peroxy Acetyl Nitrate (PAN) is the secondary pollutant which affects eys.

17. In IR spectrum of organic compound, a strong peak at 1720 cm- is due to





... Answer is c)
Explanation: In IR spectrum of organic compound, a strong peak at 1720 cm- is due to C=O bond. FBISE Chemistry 2018 Group 1

FBISE Chemistry group 1 2019

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