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NEET Chemistry Solved Question Paper 2012

Multiple Choice Questions

11.

$S_{2} O_{8}^{2 -}$ have

S-S bond
S-O bridge
O-O bridge
All S-O bond lengths are same.

12.

N-N bond length is minimum in

N₂O
N₂O₃
N₂O₄
N₂O₅

13.

Assertion : Diamond and graphite do not have the same crystal structure.

Reason : Diamond is crystalline while graphite is amorphous.

If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.

14.

Assertion : Bohr model fails in case of multielectron pecies.

Reason : It does not mention electron-electron interactions.

If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.

15.

Assertion : ClF₃has T-shape structure.

Reason : It has two lone pairs arranged at 180° angle.

If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false

16.

Assertion : O₂is paramagnetic.

Reason : It has one unpaired electron.

If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.

17.

Assertion : In a pressure cooker, the water is brought to boil. The cooker is then removed from the stove. Now on removing the lid of pressure cooker, the water starts boiling again.

Reason: The impurities in water bring down its boiling point.

If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.

18.

For silicon which is not correct?

It is a type of silicate.
It is thermally unstable.
It is hydrophilic.
Repeating unit is R₂SiO.

19.
If Si is doped with B,

n-type semiconductor is formed

p-type semiconductor is formed

insulator is formed

polymer is formed.

p-type semiconductor is formed

Silicon belongs to group 14, it is doped with a group 13 element like B which contains only three valence electrons. The place where the fourth valence e is missing is called electron hole. Under the electric field, e holes moves toward the negatively charged plate, which implies that e^- holes are positively charged, thus it is a p-type semiconductor.