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NEET Chemistry Solved Question Paper 2008

Multiple Choice Questions

1.

Assertion : The quantized energy of an electron is largely determined by its principal quantum number.

Reason : The principal quantum number n is a measure of the most probable distance of finding the electron around the nucleus.

• 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.

A.

If both assertion and reason are true and reason is the correct explanation of assertion.

where n = principal quantum number which has only integral value, it follows that total energy is quantized.

2.

Assertion : Copper metal gets readily corroded in acidic aqueous solution.

Reason : Free energy change for this process is negative.

• 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.

D.

If both assertion and reason are false.

Non-oxidising acids (HCl and dil.H2SO4) do not have any effect on copper. However they dissolve the metal in presence of air. As it is a nonspontaneous process so, $∆$G can not be -ve.

3.

Assertion : Many endothermic reactions that are not spontaneous at room temperature become spontaneous at high temperature.

Reason : Entropy of the system increases with increase in temperature.

• 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.

B.

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

The factor T$∆$S increases with increase in temperature.

4.

Assertion : According to Le-Chatelier's principle addition of heat to an equilibrium solid $⇌$liquid results in decrease in the amount of solid.

Reason : Reaction is endothermic, so on heating forward reaction is favoured.

• 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.

A.

If both assertion and reason are true and reason is the correct explanation of assertion

Solid+ heat $⇌$liquid. So on heating forward reaction is favoured and amount of solid will decrease.

5.

A unit cell of sodium chloride has four formula units. The edge length of the unit cell is 0.564 nm. What is the density of sodium chloride?

• 1.2 g/cm3

• 2.165g/cm3

• 3.64 g/cm3

• 4.56 g/cm3

B.

2.165g/cm3

6.

The correct order of increasing [H3O+] in the following aqueous solutions is

• 0.01 M H2S < 0.01 M H2SO4 < 0.01M NaCl< 0.01 M NaNO2

• 0.01 M NaCl<0.01 M NaNO2 <0.01 M H2S <0.01 M H2SO4

• 0.01 M NaNO< 0.01 M NaCl < 0.01 M H2S <0.01 M H2SO4

• 0.01 M H2S < 0.01 M NaNO2 < 0.01 M NaCl <0.01M H2SO4

C.

0.01 M NaNO< 0.01 M NaCl < 0.01 M H2S <0.01 M H2SO4

H2SO4 is strong acid having pH< 7. NaNO2 on hydrolysis gives alkaline solution of pH > 7.NaCl is neutral and H2S is weak acid.

7.

Assertion : If H2 and Cl2 enclosed separately in the same vessel exert pressure of 100 and 200 mm respectively, their mixture in the same vessel at the same temperature will exert a pressure of 300 mm.

Reason : Dalton's law of partial pressures states that total pressure is the sum of partial pressures.

• 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.

D.

If both assertion and reason are false.

Hand Clreact chemically. Hence Dalton's law is not applicable. Dalton's law states that "at a given temperature, the total pressure exerted by two or more non-reacting gases occupying a definite volume is equal to the sum of the partial pressures of the component gases."

8.

The dissociation equilibrium of a gas AB2 can be represented as

The degree of dissociation is x and is small compared to 1. The expression relating the degree of dissociation (x) with equilibrium constant KP and total pressure p is

• (2Kp/p)1/2

• Kp/p

• 2Kp/p

• (2kp/p)1/3

D.

(2kp/p)1/3

Initial            2              0          0

Equilibrium 2(1-x)         2x         x

Moles at equilibrium = 2(1-x)+2x+x =2-2x +2x+x

= x+2

9.

Percentage of Se (at. mass= 78.4) in peroxidase anhydrase enzyme is 0.5% by weight, then minimum molecular mass ofperoxidase anhydrase enzyme is

• 1.576 x 104

• 1.576 X 103

• 15.76

• 2.136 X 104.

A.

1.576 x 104

The enzyme must contains at least one atom of Se.

0.5 g of Se is present in 100gm of enzyme

78.4 g of Se will be present in =

10.

The correct order of dipole moment is

• CH4 <NF<NH<H2O

• NF3 <CH4 <NH3 <H2O

• NH3 <NF3 <CH4 <H2O

• H2O <NH3 <NF<CH4

A.

CH4 <NF<NH<H2O

In H2O electronegativity difference is highest. So, dipole moment is highest in this. CH4 is a symmetrical tetrahedral structure and its dipole moment is zero.