Chemistry

Solutions and Vapour Pressure

62 Questions

Solutions and vapour pressure questions explore boiling points, colligative properties, and osmotic pressure. These concepts are regularly tested in competitive chemistry exams. Solving these requires a solid grasp of solute and solvent interactions.

colligative propertiesvapour pressureboiling and melting pointsosmotic pressure

Solutions and Vapour Pressure Questions

Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

The vapour pressure of pure $A$ is $10$ torr and at the same temperature when $1\ g$ of $B$ is dissolved in $20\ g$ of $A$, its vapour pressure is reduced to $9.0$ torr. If the molecular mass of $A$ is $200\ amu$, then the molecular mass of $B$ is:

  1. $100\ amu$
  2. $90\ amu$
  3. $75\ amu$
  4. $120\ amu$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

So $0.1=\dfrac{moles \,\, of \,\, B}{moles of A+B}$

$0.1=\dfrac{1/m^2}{\dfrac{1}{m _2}+\dfrac{20}{200}}$
$0.1=\dfrac{1/m _2}{\dfrac{1}{m _2}+0.1}$
$\dfrac{0.1}{m _2}+0.01=\dfrac{1}{m _2}-\dfrac{0.1}{m _2}$
$0.01=\dfrac{0.9}{m _2}$
$m _2=\dfrac{0.9}{0.01}=90amu$

Multiple choice chemistry nitrogen and sulfur nitrogen gas component of air - nitrogen nitrogen

Which is the volatile covalent liquid at $25^\circ\text C$ and 1 atm ?

  1. N$ _2$

  2. Kl
  3. CCl$ _4$
  4. AgNO$ _3$
  5. CaCO$ _3$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Usually, compounds comprising of only non-metals tend to have covalent bonds. Therefore, among the given options, only A and C are covalent compounds. However, between the two, $N _2$ exists as a gas. $CCl _4$ is a covalent compound that exists as a liquid at standard temperature and pressure.

Multiple choice chemistry world energy needs coal petroleum non-renewable sources of energy

During fractional distillation, at what temperature range is carbolic oil or middle oil collected?

  1. upto 170$^o$
  2. 170 - 230 $^o$
  3. 230 - 270 $^o$
  4. 270-360$^o$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

During fractional distillation,  carbolic oil or middle oil is collected up to 170 - 230 $^o$.

Above this temperature, the Anthracene oil is obtained.

Multiple choice

Which of the following characteristics is not possessed by an ideal solution:

  1. obeys Raoult’s law.

  2. volume change on mixing is not equal to zero.

  3. there should be no chemical reaction between solute and solvent.

  4. only very dilute solutions behave as ideal solutions.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In an ideal solution, the enthalpy change and volume change upon mixing are both zero. Therefore, stating that volume change is not equal to zero describes a non-ideal solution.

Multiple choice carbohydrates - definition and classification introduction to carbohydrates biomolecules chemistry

Out of $1$M glucose and $2$M glucose. 2M glucose has  a higher boiling point.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

2 M glucose has a higher boiling point than 1 M of glucose.

Since on increasing the no of moles the molality also increases which is directly proportional to an elevation in boiling point.
Thus, the boiling point of the 2M of glucose will be greater than 1M glucose.

Multiple choice physics behaviour of perfect gas and kinetic theory of gases degree of freedom: law of equipartition of energy law of equipartition of energy law of equipartition of energy and mean free path

The mass of glucose that should be dissolved in 100 g of water in order to produce same lowering of vapour pressure as is produced by dissolving 1 g of urea (mol. Mass = 60) in 50 g of water is : (Assume dilute solution in both cases) 

  1. 1 g

  2. 2 g

  3. 6 g

  4. 12 g
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Relative lowering of vapor pressure is proportional to the mole fraction of the solute. For dilute solutions, (n_glucose / n_water1) = (n_urea / n_water2). (m_glucose / 180) / (100 / 18) = (1 / 60) / (50 / 18). Solving for m_glucose gives 6 g.

Multiple choice

What is the equation for the chemical potential of a substance?

  1. μ = (∂G/∂n)T,P

  2. μ = (∂H/∂n)T,P

  3. μ = (∂S/∂n)T,P

  4. μ = (∂U/∂n)T,P
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The chemical potential of a substance is equal to the partial derivative of the Gibbs free energy of the system with respect to the number of moles of the substance, at constant temperature and pressure.

Multiple choice

What is the equation for the Clausius-Clapeyron equation?

  1. ln(P_2/P_1) = ΔH_vap / (R * (T_2 - T_1))

  2. ln(P_2/P_1) = ΔH_vap / (R * (T_1 - T_2))

  3. ln(P_2/P_1) = -ΔH_vap / (R * (T_2 - T_1))

  4. ln(P_2/P_1) = -ΔH_vap / (R * (T_1 - T_2))
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Clausius-Clapeyron equation relates the vapor pressure of a liquid to its temperature.

Multiple choice

The Clausius-Clapeyron equation relates:

  1. The vapor pressure of a liquid to the temperature.

  2. The boiling point of a liquid to the pressure.

  3. The freezing point of a liquid to the pressure.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The Clausius-Clapeyron equation relates the vapor pressure of a liquid to the temperature, the boiling point of a liquid to the pressure, and the freezing point of a liquid to the pressure.

Multiple choice

What is the formula for calculating relative humidity?

  1. $$RH = \frac{P_{wv}}{P_{sat}} \times 100%$$
  2. $$RH = \frac{P_{sat}}{P_{wv}} \times 100%$$
  3. $$RH = \frac{P_{wv}}{P_{atm}} \times 100%$$
  4. $$RH = \frac{P_{atm}}{P_{wv}} \times 100%$$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The formula for calculating relative humidity is $$RH = \frac{P_{wv}}{P_{sat}} \times 100%$$, where $$P_{wv}$$ is the partial pressure of water vapor in the air, $$P_{sat}$$ is the saturation vapor pressure of water at the given temperature, and $$RH$$ is the relative humidity.