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# NEET Chemistry Solved Question Paper 2012

#### Multiple Choice Questions

1.

The most basic element is

• fluorine

• iodine

• chlorine

• bromine

B.

iodine

The basic nature of elements increases from top to bottom in a group. Therefore, iodine is the most basic element.

F2 < Cl2 < Br2 < I2

2.

For the homogeneous reaction,

4NH3 + 5O2 $⇌$ 4NO + 6H2O

the equilibrium constant Kc has the units

• conc.+10

• conc.+1

• conc.-1

• it is dimensionless

B.

conc.+1

For the given reaction, $∆$ng = np - nr

(where, np = number of moles of gaseous products and nr = number of moles of gaseous reactants)

$∆$ng = (6 + 4) - (4 + 5) = +1

Units of Kc = (concentration)$∆$ng

= (concentration)+1

3.

Which of the following has sp2-hybridisation?

• C2H6

• C2H4

• BeCl2

• C2H2

B.

C2H4

When there are 3$\mathrm{\sigma }$ bonds, the hybridisation is sp2. The structures of the given compounds are

a. C2H

b. C2H-

c. BeCl2 -

d. C2H2

4.

Consider the following reaction,

C6H5NO2  X $\stackrel{{\mathrm{C}}_{6}{\mathrm{H}}_{5}\mathrm{COCl}}{\to }$ Y + HCl

What is Y?

• Acetanilide

• Benzinilide

• Azobenzene

• Hydrazobenzene

B.

Benzinilide

In the above reaction, Y represents Benzinilide.

5.

The correct order of decreasing first ionisation energy is

• C > B > Be > Li

• C > Be > B > Li

• B > C > Be > Li

• Be > Li > B > C

B.

C > Be > B > Li

On moving from left to right in a period, as the size decreases, ionisation energy increases. But first I E of elements of II A group is higher than that of the elements of III A group because of the stable ns configuration (of II A group). Hence, the order of first ionisation energy is

C > Be > B > Li

6.

The pH value of 0.001 M aqueous solution of NaCl is

• 7

• 4

• 11

• unpredictable

A.

7

NaCl is a neutral salt, thus the pH value of its aqueous solution is 7.

7.

Ammonia is a Lewis base and it forms complexes with many cations. Which one of the following cations does not form a complex with ammonia?

• Ag+

• Cu2+

• Cd2+

• Pb2+

D.

Pb2+

Ammonia is a Lewis base. It forms complexes with transition elements like Ag+, Cu2+ and Cd2+ while it does not form complex with Pb2+ because Pb is not a transition element.

AgCl + 2NH4OH $\to$ [Ag(NH3)2]Cl + 2H2O

CuSO4 + 4NH4OH $\to$[Cu(NH3)4]SO4 + 4H2O

CdSO4 + 4NH4OH $\to$[Cd(NH3)4SO4 + 4H2O

8.

Argol, a brown crust, formed during the fermentation of grape juice contains

• CO2

• fused oil

• potassium hydrogen tartarate

• lye

C.

potassium hydrogen tartarate

Argol consists of potassium hydrogen tartarate.

9.

Which buffer solution comprising of the following has its pH value greater than 7?

• CH3COOH + CH3COONa

• HCOOH + HCOOK

• CH3COONH4

• NH4OH + NH4Cl

D.

NH4OH + NH4Cl

The pH value of basic buffer solutions is always greater than 7. Among the given, only NH4OH + NH4Cl constitutes the basic buffer (a mixture of weak base and its conjugated salt), thus, has pH greater than 7.

10.

Which one of the following sets of quantum numbers represents the highest energy level in an atom?

• n = 4; l = 0; m = 0; s = +$\frac{1}{2}$

• n = 3; l = 1; m = 1; s = +$\frac{1}{2}$

• n = 3; l = 2; m = -2; s = +$\frac{1}{2}$

• n = 3; l = 0; m = 0; s = +$\frac{1}{2}$

C.

n = 3; l = 2; m = -2; s = +$\frac{1}{2}$

In order to have highest energy level in an atom, n + l shoud be maximum. Therefore, option c is correct.