Solutions - Physical Chemistry - Chemistry Previous Year Questions

1

2008 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2008

According to the Debye-Hückel limiting law, the mean activity coefficient of 5 x 10^-4 mol kg^-1 aqueous solution of CaCl₂ at 25 °C is (the Debye-Hückel constant 'A' can be taken to be 0.509)

A

0.63

B

0.72

C

0.80

D

0.91

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2

2009 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2009

Among the following, the system that would require the least amount of thermal energy to bring its temperature to 80 °C is

A

200 g of water at 40 °C

B

100 g of water at 20 °C

C

150 g of water at 50 °C

D

300 g of water at 30 °C

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3

2009 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2009

According to the Debye-Hückel limiting law, if the concentration of a dilute aqueous solution of KCl is increased 4-fold, the value of ln γ± (γ± is the molal mean ionic activity coefficient) will

A

decrease by a factor of 2

B

increase by a factor of 2

C

decrease by a factor of 4

D

increase by a factor of 4

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4

2009 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2009

Two liquids B and C form an ideal solution. In the figure below, the vapour pressure P of this solution is shown as a function of the mole fraction, XB, of component B. Given a state of this vapour-liquid mixture whose overall composition corresponds to point E in the figure, the mole fraction of B in the vapour phase is approximately

A

0.25

B

0.53

C

0.65

D

0.80

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5

2011 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2011

The freezing point constant for water is 1.86 K (mol kg^-1)^-1. The change in freezing point when 0.01 mol glucose is added to 1 kg water is

A

1.86 K

B

-1.86 K

C

0.186 K

D

-0.0186 K

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6

2011 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2011

The activity of water at 11 bar and 298 K is

A

1.101

B

1.007

C

0.998

D

0.898

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7

2011 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2011

For the process
\[1\ \text{Ar (300 K, 1 bar)} \rightarrow 1\ \text{Ar (200 K, 10 bar)}\]
assuming ideal gas behavior, the change in molar entropy is

A

\(-27.57\ \text{J K}^{-1}\ \text{mol}^{-1}\)

B

\(+27.57\ \text{J K}^{-1}\ \text{mol}^{-1}\)

C

\(-24.20\ \text{J K}^{-1}\ \text{mol}^{-1}\)

D

\(+24.20\ \text{J K}^{-1}\ \text{mol}^{-1}\)

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8

2011 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2011

There are two candidates P and Q in an election. During the campaign, 40% of the voters promised to vote for P, and rest for Q. However, on the day of election 15% of the voters went back on their promise to vote for P and instead voted for Q. 25% of the voters went back on their promise to vote for Q and instead voted for P. Suppose, P lost by 2 votes, then what was the total number of voters?

A

100

B

110

C

90

D

95

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9

2011 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2011

Three friends, R, S and T shared toffee from a bowl. R took 1/3^rd of the toffees, but returned four to the bowl. S took 1/4^th of what was left but returned three toffees to the bowl. T took half of the remainder but returned two back into the bowl. If the bowl had 17 toffees left, how many toffees were originally there in the bowl?

A

38

B

31

C

48

D

41

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10

2012 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2012

If \( x_A \) and \( x_B \) are the respective mole fractions of A and B in an ideal solution of the two and \( T_A, T_B, T \) are the fusion temperatures of pure A, pure B and the ideal solution respectively, then

A

\(1-x_B = \exp \left[ \frac{-\Delta H_{fus(A)}}{R} \left( \frac{1}{T} - \frac{1}{T_A} \right) \right] \)

B

\(1-x_B = \exp \left[ \frac{\Delta H_{fus(B)}}{R} \left( \frac{1}{T} - \frac{1}{T_A} \right) \right] \)

C

\(1-x_B = \exp \left[ \frac{\Delta H_{fus(B)}}{R} \left( \frac{1}{T} - \frac{1}{T_B} \right) \right] \)

D

\(1-x_B = \exp \left[ \frac{-\Delta H_{fus(A)}}{R} \left( \frac{1}{T} - \frac{1}{T_A} \right) \right] \)

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11

2012 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2012

The data given in the following table summarizes the monthly budget of an average household.

Category	Amount (Rs.)
Food	4000
Clothing	1200
Rent	2000
Savings	1500
Other expenses	1800

The approximate percentage of the monthly budget NOT spent on savings is

A

10%

B

14%

C

81%

D

86%

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12

2012 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2012

Raju has 14 currency notes in his pocket consisting of only Rs. 20 notes and Rs. 10 notes. The total money value of the notes is Rs. 230. The number of Rs. 10 notes that Raju has is

A

5

B

6

C

9

D

10

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13

2013 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2013

A 2 L vessel containing 2 g of $H_2$ gas at 27 °C is connected to a 2 L vessel containing 176 g of $CO_2$ gas at 27 °C. Assuming ideal behavior of $H_2$ and $CO_2$, the partial pressure of $H_2$ at equilibrium is ______ bar.

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14

2013 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2013

Select the pair that best expresses a relationship similar to that expressed in the pair:
water : pipe :

A

cart : road

B

electricity : wire

C

sea : beach

D

music : instrument

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15

2013 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2013

Following table gives data on tourists from different countries visiting India in the year 2011.

Country	Number of Tourists
USA	2000
England	3500
Germany	1200
Italy	1100
Japan	2400
Australia	2300
France	1000

Which two countries contributed to the one third of the total number of tourists who visited India in 2011?

A

USA and Japan

B

USA and Australia

C

England and France

D

Japan and Australia

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16

2014 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2014

A plot of osmotic pressure against concentration (g L⁻¹) of a polymer is constructed. The slope of the plot

A

increases with increase in temperature

B

increases with increase in molar mass of the polymer

C

decreases with decrease in concentration of the polymer

D

decreases with increase in temperature

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17

2016 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2016

A protein sample consists of an equimolar mixture of ribonuclease (molar mass = 13.7 kg mol^-1), hemoglobin (molar mass = 15.5 kg mol^-1), and myoglobin (molar mass = 17.2 kg mol^-1). The statement that is true about the weight-average molar mass (M̄_w), the number-average molar mass (M̄_n), and the polydispersity index (PDI) for this sample is

A

M̄_w > M̄_n = 15.5 kg mol^-1 and PDI > 1

B

M̄_w > M̄_n = 15.5 kg mol^-1 and PDI < 1

C

M̄_w = 15.5 kg mol^-1 > M̄_n and PDI > 1

D

M̄_w = 15.5 kg mol^-1 < M̄_n and PDI < 1

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18

2019 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2019

On heating a sample of 25 mg hydrated compound (molecular weight = 250 g/mol) in thermogravimetric analysis, 16 mg of dehydrated compound remains. The number of water molecules lost per molecule of hydrated compound is __________.
(Molecular weight of water = 18 g/mol)

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19

2023 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2023

Two-component solid-liquid system of naphthalene-benzene forms a simple eutectic mixture. Assuming that naphthalene-benzene forms an ideal solution, the mole fraction of naphthalene in benzene at 300 K and 1 bar is ______ (rounded off to two decimal places)
(Given: Freezing point ($T_{fp}$) and enthalpy of fusion ($\Delta H_{fus}$) of naphthalene are 353 K and 19.28 kJ mol⁻¹, respectively and gas constant ($R$) = 8.31 J K⁻¹ mol⁻¹)

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20

2023 · Chemistry · Physical Chemistry · Solutions

Chemistry (CY) 2023

The intrinsic viscosity of a sample of polystyrene in toluene is 84 cm³ g⁻¹ at 30 °C. It follows Mark-Houwink equation with empirical constant values of $K = 1.05 \times 10^{-2}$ cm³ g⁻¹ and $\alpha = 0.75$. The molecular weight of the polymer is ______ × 10⁵ g mol⁻¹ (rounded off to the nearest integer)

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