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# NEET Chemistry Solved Question Paper 2009

#### Multiple Choice Questions

1.

For endothermic reaction :

• Ea > Ea'

• Ea = Ea'

• Ea < Ea'

• None of these

A.

Ea > Ea'

If the potential energy ofthe products is greater than that of the reactants , the energy released in going from the activated complex to products will be less than the activation energy and reaction willbe endothermic .

A + B $\stackrel{{\mathrm{E}}_{\mathrm{a}}}{\to }$  $\stackrel{{{\mathrm{E}}_{\mathrm{a}}}^{\text{'}}}{\to }$

Ea > Ea'

2.

When ${}_{13}{}^{27}\mathrm{Al}$ is bombarded with $\mathrm{\alpha }$ - particle , a radioactive isotope of phosphorus ${}_{15}{}^{30}\mathrm{P}$ is formed .Which particle is emitted along with ${}_{15}{}^{30}\mathrm{P}$ ?

• Deuteron

• Proton

• Electron

• Neutron

D.

Neutron

when ${}_{13}{}^{27}\mathrm{Al}$ is bombarded with $\mathrm{\alpha }$ - particle , then ${}_{15}{}^{30}\mathrm{P}$ is formed along with ${}_{0}{}^{1}\mathrm{n}$ .

${}_{13}{}^{27}\mathrm{Al}$ + ${}_{4}{}^{2}\mathrm{He}$ $\to$ ${}_{15}{}^{30}\mathrm{P}$ + ${}_{0}{}^{1}\mathrm{n}$

3.

The product formed is an isobar , if there is :

• $\mathrm{\alpha }$ emission

• $\mathrm{\beta }$ emission

• $\mathrm{\alpha }$ and 1 $\mathrm{\beta }$ emission

• $\mathrm{\alpha }$ and 2 $\mathrm{\beta }$ emission

B.

$\mathrm{\beta }$ emission

${}_{\mathrm{n}}{}^{\mathrm{m}}\mathrm{X}$

The atoms of different elements having different atomic number but same mass number are called isobars .So , by emission of one $\mathrm{\beta }$ particle isobar is obtained .

4.

Solution of 0.l N NH4OH and 0.1 N NH4Cl has pH 9.25. Then , pKb of NH4OH is :

• 9.75

• 4.75

• 3.75

• 8.25

B.

4.75

pOH = pKb + log$\frac{\left[\mathrm{salt}\right]}{\left[\mathrm{base}\right]}$

$\because$  [NH4Cl] = [NH4OH]

$\because$   pOH = pKb

pKb = pOH = 14 - pH

= 14 - 9.25 = 4.75

5.

How many grams of CO2 will be produced by the complete combustion of 2 moles of ethanol ?

• 132 g

• 44 g

• 176 g

• 88 g

C.

176 g

+ 3O2 $\to$  + 3H2O

1 mole (46 g) C2H5OH gives = 88 g CO2

2 moles (92 g) C2H5OH will give = 176 g CO2

6.

The difference between heat of reaction at constant pressure and constant volume of the reaction :

2C6H6 (l) + 15O2 (g) $\to$ 12CO2 + 6H2O (l)

at 25°C (in kJ) is :

• - 7.43

• 3.72

• - 3.72

• 7.43

A.

- 7.43

$⇒$ $∆$H = $∆$E + $∆$ngRT

$\therefore$     $∆$H - $∆$E = $∆$ngRT

= - 3 x 8.314 x 10-3 x 298

= - 7.43kJ

7.

Heat of combustion of C and CO are -394 and -285 kJ respectively , so heat of formation of CO in kJ/mol is :

• - 218

• - 109

• + 109

• + 218

B.

- 109

C (s) + $\frac{1}{2}$ O2 (g) $\to$ CO (g)

$∆$H = - [${∆}_{\mathrm{c}}$ H of CO - ${∆}_{\mathrm{c}}$ H of C]

= - [-285-(-394)] kJ

= - 109 kJ

8.

Which of the following changes with change in temperature ?

• Mole fraction

• Formality

• % (w/W)

• Molality

B.

Formality

Formality is the-number of formula weights present in one litre of the solution .Formality changes withtemperature because it involves volume which change with temperature .

9.

The concentration of Ag+ ion in a given saturated solution of AgCl at 25°C is 1.06 x 10-5 g ion L-1 .Thus , the solubility product of AgCl is :

• 0.453 x 10-10

• 0.530 x 10-10

• 1.12 x 10-10

• 2.12 x 10-10

D.

2.12 x 10-10

AgCl $⇌$ $\underset{\mathrm{s}}{{\mathrm{Ag}}^{+}}$ + $\underset{\mathrm{s}}{{\mathrm{Cl}}^{-}}$

[Ag+] = [Cl-] = 1.06 x 10-5 g ion/L

Ksp = [Ag+] [Cl-] = S2

= (1.06 X l0-5)2 = 1.12 X 10-10

10.

For which reaction will $∆$H - $∆$E = 0 ? Assume that each reaction is carried out in an open container .

• 2CO2 (g) + O2 (g) $\to$ 2CO2 (g)

• PCl5 (g) $\to$ PCl3 (g) + Cl2 (g)

• H2 (g) + Br2 (g) $\to$ 2HBr (g)

• C (s) + 2H2O (g) $\to$ 2H2 (g) + CO2 (g)

C.

H2 (g) + Br2 (g) $\to$ 2HBr (g)

$∆$H = $∆$E + $∆$ngRT

For reaction H2 (g) + Br2 (g) $\to$ 2HBr (g)

$∆$ng = 0 , while for other $∆$ng $\ne$ 0

Thus , $∆$H = $∆$E + 0 x RT

$∆$H - $∆$E = 0