NEET Class 12

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NEET Chemistry Solved Question Paper 2004

Multiple Choice Questions

1.

Which of the following salt does not get hydrolysed in water ?

• KClO4

• NH4Cl

• CH3COONa

• None of these

A.

KClO4

Only salts of (weak acid + strong base) and (strong acid + weak base) get hydrolysed (i.e., show alkalinity or acidity in water) . KClOis a salt of strong acid and strong base ,therefore it does not get hydrolysed in water .

KClO4 $⇌$ K+ + ClO4-

H2$⇌$

2.

KI and CuSO4 solution when mixed , give :

• CuI2 + K2SO4

• Cu2I2 + K2SO4

• K2SO+ Cu2I2 + I2

• K2SO+ CuI2 + I2

C.

K2SO+ Cu2I2 + I2

2KI + CuSO4 $\to$ $\underset{\mathrm{unstable}}{{\mathrm{CuI}}_{2}}$ + K2SO4

2CuI2 $\to$ Cu2I2 + I2

Hence , solution contains K2SO+ Cu2I2 + I2

3.

Which among the following elements have lowest value of IE1 ?

• Pb

• Sn

• Si

• C

B.

Sn

The ionisation energy of Tin (Sn) is less than that of lead (Pb) .It is due to the poor sheilding of d - and f - electron in Pb due to which it feels greater attraction from nucleus .

4.

Which of the following element is a metalloid ?

• Bi

• Sn

• Ge

• C

C.

Ge

Boron (B) , Si , Ge , As , Sb , Te and At are the metalloid elements .Bismuth (Bi) and tin (Sn) are metals while carbon (C) is non-metal .

5.

What will be the pH value of 0.05 M Ba(OH)2 solution ?

• 12

• 13

• 1

• 12.96

B.

13

0.05 M Ba(OH)2 Solution

= 2 x 0.05 N Ba(OH)2

= 0.10 N Ba(OH)2

$\therefore$ pOH = -log [OH-]

= - log (0.10) = 1

pH = 14 - pOH

= 14 - 1 = 13

6.

In the reaction :

H2 + I2 $⇌$ 2HI

In a 2 litre flask 0.4 moles of each H2 and I2 are taken .At equilibrium 0.5 moles of HI are formed .What will be the value of equilibrium constant ,Kc ?

• 20.2

• 25.4

• 0.284

• 11.11

D.

11.11

Kc$\frac{\left[\mathrm{HI}{\right]}^{2}}{\left[{\mathrm{H}}_{2}\right]\left[{\mathrm{I}}_{2}\right]}$ $\frac{{\left(\frac{0.50}{2}\right)}^{2}}{\left(\frac{0.15}{2}\right)\left(\frac{0.15}{2}\right)}$

= 11.11

 H2 + I2 $⇌$ 2HI 0.4 0.4 0.50 At equilibrium 0.4- 0.25 0.4 - 0.25 0.50 = 0.15 = 0.15

7.

Which of the following elements never show positive oxidation number ?

• O

• Fe

• Ga

• F

D.

F

Fluorine is the most electronegative element in the periodic table so it never shows positive oxidation state .

8.

Ionisation depends upon :

• pressure

• volume

• dilution

• none of these

C.

dilution

Ionisation depends upon concentration , temperature , nature of solute and on nature of solvent .Ionisation increases on increasing dilution .

9.

The first ionisation potential is maximum for :

• B

• N

• O

• Be

B.

N

Ionisation potential generally increase when we move in a period from left to right but IE1 of N2 is greater than that of O2 .It is due to the more stable (half-filled orbitals) configurations of N .

10.

The solubility of in water is Sb2S3 in water is 1.0 x 10-5 mol/litre at 298 K .What will be its solubility product ?

• 108 x 10-25

• 1.0 x 10-25

• 144 x 10-25

• 126 x 10-25

A.

108 x 10-25

$⇌$ $\underset{2\mathrm{s}}{2{\mathrm{Sb}}^{3+}}$ + $\underset{3\mathrm{s}}{3{\mathrm{S}}^{2-}}$

Solubility product

(Ksp) = [Sb3+]2 [S2]3

= (2s)2 (3s)3

= 108 s5

= 109 x (1.0 x 10-5)5

= 108 x 10-25