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# NEET Chemistry Solved Question Paper 2008

#### Multiple Choice Questions

1.

During the formation of a chemical bond :

• electron-electron repulsion becomes more than the nucleus-electron attraction

• energy of the system does not change

• energy increases

• energy decreases

D.

energy decreases

During the formation of a chemical bond energy decreases .

2.

Molarity of a given orthophosphoric acid solution is 3 M .It's normality is :

• 9 N

• 0.3 N

• 3 N

• 1 N

A.

9 N

Orthophosphoric acid (H3PO4) is a tribasic acid .

$\because$ Normality = Molarity x basicity

$\because$  Normality = 3M x 3

= 9 N

3.

2SO2 (g) + O2 (g)   is an example for :

• neutralisation reaction

• homogeneous catalysis

• heterogeneous catalysis

• irreversible reaction

C.

heterogeneous catalysis

2SO2 (g) + O2 (g) $\stackrel{{\mathrm{V}}_{2}{\mathrm{O}}_{5}}{⇌}$ 2SO3 (g)

In this reaction , reactants as well as the catalyst are present in more than one phase , hence it is an example of heterogeneous catalysis .

4.

Which ofthe following is an intensive property ?

• Temperature

• Viscosity

• Surface tension

• All of these

D.

All of these

The properties of the system whose value is independent of the amount of substance present in the system , are called intensive properties . eg , viscosity , surface tension , temperature , pressure etc .

5.

For a certain particle , it is found that uncertainty in velocity is reciprocal of uncertainty in position .This implies that :

• mass of particle > unity

• mass of particle = unity

• mass of particle $\le$ h

• mass of particle $\ge$ h / 4$\mathrm{\pi }$

D.

mass of particle $\ge$ h / 4$\mathrm{\pi }$

According to Heisenberg's uncertainty principle

$∆$x . $∆$$\ge$ $\frac{\mathrm{h}}{4\mathrm{\pi }}$     ($\because$ $∆$p = m$∆$v)

$∆$x . m . $∆$$\ge$ $\frac{\mathrm{h}}{4\mathrm{\pi }}$

Given , $∆$x = $\frac{1}{∆\mathrm{\nu }}$

Thus ,   m $\ge$ $\frac{\mathrm{h}}{4\mathrm{\pi }}$

6.

Hydroxyl ion concentration of 10-2 M HCl is :

• 1 x 101 mol dm-3

• 1 x 10-12 mol dm-3

• 1 x 10-1 mol dm-3

• 1 x 10-14 mol dm-3

B.

1 x 10-12 mol dm-3

[H+] [OH-] = 10-14

[10-2] [OH-] = 10-14

[OH-] = $\frac{{10}^{-14}}{{10}^{-2}}$

= 10-12 mol dm-3

7.

In equilibrium state , the value of $∆$G is :

• zero

• negative

• positive

• may be negative or positive

A.

zero

In the equilibrium state the value of $∆$G is zero .

8.

Which one of the following salts on being dissolved in water gives pH > 7 at 25°C ?

• KCN

• KNO3

• NH4Cl

• NH4CN

A.

KCN

KCN is a salt of weak acid and strong base hence on being dissolved in water it gives basic ,solution ie, pH > 7 at 25°C .

9.

The volume of 10N and 4N HCl required to make 1 L of 7N HCl are :

• 0.50 L of 10N HCl and 0.50 L of 4N HCl

• 0.60 L of 10N HCl and 0.40 L of 4N HCl

• 0.80 L of 10N HCl and 0.20 L of 4N HCl

• 0.75 L of 10N HCl and 0.25 L of 4N HCl

A.

0.50 L of 10N HCl and 0.50 L of 4N HCl

Let V litre of 10 N HCl be mixed with (1 - V) litre of 4N HCl to give (V + 1 - V) = 1 L of 7N HCl .

N1V1 + N2V2 = N V

10V + 4 (1 - V) = 7 x 1

10 V + 4 - 4 V = 7

6 V = 7 - 4

V = $\frac{3}{6}$ = 0.50 L

Volume of 10 N HCl = 0.50 L

Volume of 4 N HCl = 1 - 0.50 = 0.50 L

10.

Entropy of the universe is :

• constant

• zero

• continuously decreasing

• continuously increasing

D.

continuously increasing

According to second law of thermodynamics , the entropy of the universe always increases in the course of every spontaneous (natural) change .