﻿ Smallest wavelength occurs for from Chemistry NEET Year 2011 Free Solved Previous Year Papers

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# 1.Smallest wavelength occurs forLyman series Balmer series Paschen series Brackett series

A.

Lyman series

Smallest wavelength occurs in Lyman series.

Wavelength increases from Lyman > Balmer > Paschen > Brackett > Pfund.

2.

In the van der Waals equation, 'a' signifies

• intermolecular attraction

• intramolecular attraction

• attraction between molecules and wall of container

• volume of molecules

A.

intermolecular attraction

In van der Waal's equation, a signifies the intermolecular force of attraction.

3.

Ksp of CaSO4.5H2O is 9 $×$10-6, find the volume for 1 g of CaSO4(M.wt. = 136).

• 2.45 litres

• 5.1 litres

• 4.52 litres

• 3.2 litres

A.

2.45 litres

CaSO4 (s)$⇌\underset{\mathrm{S}}{{\mathrm{Ca}}^{2+}}\left(\mathrm{aq}\right)+\underset{\mathrm{S}}{{\mathrm{SO}}_{4}^{2-}}\left(\mathrm{aq}\right)$

Ksp = S2 = 9$×$ 10-6

S = 3$×$ 10-3 mol L-1

Solubility in g litre-1 = molecular mass$×$S

= 136$×$ 3$×$ 10-3 = 408$×$ 10-3 g L-1

408$×$ 10-3 g of CaSO4 present in 1 litre.

1 gm of CaSO4 present is$\frac{1}{408×{10}^{-3}}=2.45\mathrm{litres}$

4.

Decreasing order of bond angle is

• BeCl2 > NO2 > SO2

• BeCl2 > SO2 > NO2

• SO2 > BeCl2 > NO2

• SO2 > NO2 > BeCl2

A.

BeCl2 > NO2 > SO2

Decreasing order of bond angle is BeCl2 > NO2 > SO2.

Bond angle of BeCl2, NO2 and SO2 is 180$°$, 132$°$and 119.5$°$respectively.

5.

Which of the following is wrong for Bohr model?

• It establishes stability of atom

• It is inconsistent with Heisenberg uncertainty principle.

• It explains the concept of spectral lines for hydrogen like species.

• Electrons behave as particle and wave

D.

Electrons behave as particle and wave

Among all the given options, option d is wrong. It can be corrected as Bohr model does not explain de Broglie concept of the dual character of matter.

6.

Which of the following is not hygroscopic?

• CsCl

• MgCl2

• CaCl2

• LiCl

A.

CsCl

CsCl is not hygroscopic in nature while MgCl2, CaCl2 and LiCl are hygroscopic in nature.

7.

Predict the product of reaction of I2 with H2O2 in basic medium

• I-

• I2O3

• IO${}_{3}^{-}$

• I${}_{3}^{-}$

A.

I-

I- is the product of reaction in basic medium.

I2 (s) + H2O2 (aq) +2OH- (aq)$\to$2I- (aq) + 2H2O (l) + O2 (g)

8.

Which of the following is not a characteristic of equilibrium?

• Rate is equal in both directions

• Measurable quantities are constant at equilibrium.

• Equilibrium occurs in reversible condition.

• Equilibrium occurs only in open vessel at constant temperature.

D.

Equilibrium occurs only in open vessel at constant temperature.

Equilibrium state can only be achieved if a reversible reaction is carried out in a closed space.

9.

For adiabatic process, which is correct?

• $∆$T = 0

• $∆$S = 0

• q = 0

• qp = 0

C.

q = 0

Adiabatic process is a process that occurs without transfer of heat or mass of substances between a thermodynamic system and it surroundings. Therefore, q = 0

10.

The enthalpy of formation of CO(g), CO2(g), N2O(g), and N2O4(g) is -110, -393, +811 and 10 kJ/mol respectively. For the reaction, N2O4+ 3CO(g) $\to$ N2O(g)+ 3CO2(g);$∆$Hr (kJ/mol) is

• -212

• +212

• +48

• -48

D.

-48

N2O4(g)+ 3CO(g)$\to$N2O (g) + 3CO2 (g)

$∆{H}_{reaction}={\sum }_{\mathrm{Heat}\mathrm{of}\mathrm{formation}\mathrm{of}\mathrm{products}}-{\sum }_{\mathrm{Heat}\mathrm{of}\mathrm{formation}\mathrm{of}\mathrm{reactants}}$

${\text{∆H}}_{\mathrm{reaction}}=\left[∆{\mathrm{H}}_{\mathrm{f}}{\mathrm{N}}_{2}\mathrm{O}+3×∆{\mathrm{H}}_{\mathrm{f}}{\mathrm{CO}}_{2}\right]-\left[∆{\mathrm{H}}_{\mathrm{f}}{\mathrm{N}}_{2}{\mathrm{O}}_{4}+3×∆{\mathrm{H}}_{\mathrm{f}}\mathrm{CO}\right]\phantom{\rule{0ex}{0ex}}∆{\mathrm{H}}_{\mathrm{r}}=\left[+811+3\left(-393\right)\right]-\left[10+3\left(-110\right)\right]$

= [811 - 1179] - [-320]

= -368 + 320

= -48 kJ/mol