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# NEET Chemistry Solved Question Paper 2005

#### Multiple Choice Questions

1.

a/ V2 given in van der Waal's equation is for

• internal pressure

• inter molecular attraction

• both (1) and (2)

• temperature correction

B.

inter molecular attraction

For the explaination of real gas behaviour van der Waal gave an equation. The gas pressure is changed due to intermolecular attraction. By adding $\frac{\mathrm{a}}{{\mathrm{V}}^{2}}$ the pressure value is made correct.

2.

C(dia) + O2 $\to$ CO2$∆\mathrm{H}$ = - 395.4 kJ/ mol

C(gr) + O2 $\to$CO2$∆$H   = - 393.5 kJ/ mol

C(gr) $\to$C(dia)$∆$H = ?

• -3.8

• -1.9

• +3.8

• +1.9

D.

+1.9

C(dia) + O2 $\to$CO2 ($∆$H = -395.4 kJ/mol)         ...(1)

C(gr) + O2 $\to$CO2  ($∆$H = -393.5 kJ/mol)         ...(2)

On subtarcting equation (1) from (2), we get,

C(gr) $\to$C(dia)$∆$H = +1.9 kJ/ mol

Since, $∆$H = -393.5 - (-395.4)

= +1.9 kJ mol-1

3.

Hybridization of 1 and 2 carbon atom in

$\stackrel{1}{\mathrm{C}}$H2$\stackrel{2}{\mathrm{C}}$ = CHare

• sp, sp

• sp2, sp2

• sp2, sp

• sp3, sp2

C.

sp2, sp

In this compound carbon atoms have following hybridization :

Carbon one contains one m bond and carbon two contains two m bonds and hence show sp2 and sp hybridization respectively.

4.

In an isothermal process

B.

In an isothermal process, the temperature is constant.

5.

Which has minimum solubility?

• Bi2S3

• Ag2S

• CoS

• PbS

B.

Ag2S

Solubilities of salts are as follows:

Hence, Ag2S is least soluble. Therefore, minimum solubility is of CoS as its force of attraction is greatest.

6.

Ratio of molecular weights of A and B is $\frac{4}{25}$ then ratio of rates of diffusion will be

• 5 : 1

• 5 : 2

• 25 : 3

• 25 : 4

B.

5 : 2

According to Graham's rule

Hence, ratio of diffusion is 5 : 2

7.

The pH of a 10-10M - NaOH solution is

• 10

• 7.01

• 6.99

• 4

B.

7.01

When the solution is very dilute, the concentration of OHproduced from water cannot be neglected. Hence,

[OH-]  = 10-10 + 10-7 (obtained from water)

= 10-7 (0.001 + 1)

= 1.001 $×$ 10-7

$\therefore$ pOH = -log[OH-]

= -log(1.001 $×$ 10-7)

= 7 - 0.01 = 6.99

$\therefore$ pH   = 14 - pOH

= 14 - 6.99

= 7.01

Therefore, the pH of a 10-10 - NaOH solution is 7.01

8.

Number of orbitals in L energy level

• 1

• 2

• 3

• 4

D.

4

It is second energy level. Second energy level contains one s-orbital and three p- orbitals. Therefore, total number of orbital in L level is four.

9.

The internal energy of a substance

• decrease with increase in temperature

• increase with increase in temperature

• remains unaffected with change in temperature

• calculated by E = mc2

B.

increase with increase in temperature

The internal energy of a substance always increases with increase in temperature.

10.

H-bond is strongest in

• C2H5OH

• H-F

• H2O

• CH3COCH3

B.

H-F

All compound which have hydrogen atom attached to F, O or N atom (i.e. highly electronegative atoms) exhibit H-bonding. In the question H - F exhibit strongest H-bonding because F is the most electronegative element.