Tag: chemistry

Questions Related to chemistry

Heavy water $\displaystyle \left( { D } _{ 2 }O \right) $ is used in Atomic Reactors as -

chemistry hydrogen and its compounds heavy water study of heavy water hard water and soft water

  1. Coolant

  2. Controller

  3. Shield

  4. Moderator

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Correct Option: D
Explanation:

Moderator. e.g. , Heavy water, is a substance used in nuclear reactors of reduce the speed of fast Neutrons produced by nuclear fission.Moderator. e.g. , Heavy water, is a substance used in nuclear reactors of reduce the speed of fast Neutrons produced by nuclear fission.Moderator. e.g. , Heavy water, is a substance used in nuclear reactors of reduce the speed of fast Neutrons produced by nuclear fission.'

Heavy water is used in nuclear reactors as:

chemistry hydrogen and its compounds heavy water study of heavy water hard water and soft water

  1. source of $\alpha-$ particles

  2. slowing down the speed of high energy neutrons

  3. transporting heat of the reactor

  4. heating purpose

Show answer
Correct Option: B
Explanation:

Heavy water is used in nuclear reactors, where it acts as a neutron moderator to slow down neutrons so that they are more likely to react with the fissile $U^{235}$ than with $U^{238}$, which captures neutrons without fissioning.

Heavy water is a compound of :

chemistry hydrogen and its compounds heavy water study of heavy water hard water and soft water

  1. hydrogen and heavier isotope of oxygen.

  2. heavier isotope of hydrogen and heavier isotope of oxygen.

  3. oxygen and heavier isotope of hydrogen.

  4. none of the above

Show answer
Correct Option: C
Explanation:

Heavy water is $D _2O$ and it is composed of oxygen and heavier isotope of hydrogen $(D)$.

$ \displaystyle 4{ D } _{ 2 }O+3Fe \xrightarrow[]{red-hot} Fe _{3}O _{4}+gas.$ The gas produced in the above reaction is:

chemistry hydrogen and its compounds heavy water study of heavy water hard water and soft water

  1. $ \displaystyle O _{2}$

  2. $ \displaystyle H _{2}$

  3. $ \displaystyle D _{2}$

  4. none

Show answer
Correct Option: C
Explanation:

Reaction:

$ \displaystyle 4{ D } _{ 2 }O+3Fe \xrightarrow[]{red-hot} Fe _{3}O _{4}+ D _2$. The gas produced in the reaction is deuterium.

Simple method of separating ammonia and hydrogen is :

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

  1. Passing the mixture through water

  2. Distillation

  3. Filtration

  4. Evaporation

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Correct Option: A
Explanation:

Passing the mixture through water can separate the mixture of ammonia and hydrogen. Ammonia being highly soluble dissolves in water while hydrogen passes out as gas.

Which of the following has no units?

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

  1. Molarity

  2. Normality

  3. Molality

  4. Mole fraction

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Correct Option: D
Explanation:

Mole fraction of A in solution containing A and B $=\dfrac {n _A}{n _A+n _B}=\dfrac {mole}{mole}$ which cancels out. 

Hence, it is unitless.

A drop each of two non-corrosive and non-irritating liquids A and B at a temperature of $22^o$C are placed on the skin. Liquid 'A gives a more cooling sensation than liquid B. Which of the following can be said about the liquids A and B?

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

  1. Liquid A has higher boiling point than that of liquid B

  2. Liquid A has higher latent heat of vaporization than that of liquid B.

  3. Liquid A has lower latent heat of vaporization than that of liquid B.

  4. The boiling points of liquid A and B are equal.

Show answer
Correct Option: C
Explanation:

Light A gives a more cooling sensation than liquid B means liquid A is early vaporised than liquid B. Thus, liquid A has less B P and lower latent heat of vaporisation than that of liquid B.

At higher altitudes the boiling point of liquid is lowered because :

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

  1. temperature is low

  2. pressure is high

  3. temperature is high

  4. atmospheric pressure is low

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Correct Option: D
Explanation:

A liquid reaches its boiling point when its vapor pressure is equal to the atmosphere around it.

 Because the presence of solute lower the vapor pressure, the boiling point is raised

Which of the following solutions will have the highest boiling point?

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

  1. $0.1M\quad { FeCl } _{ 3 }$

  2. $0.1M\quad { BaCl } _{ 2 }$

  3. 0.1M $NaCl$

  4. 0.1 M $Urea$

Show answer
Correct Option: A
Explanation:

Boiling point elevation depends on the solvent, of course, but we're assuming water, and upon the concentration of the solute and how many particles into which the solute breaks. Colligative properties like boiling point elevation, depend on the total number of particles in solution. The solvent used here is water. So elevation in boiling point will be above a boiling point of water for all solutions.
Boiling point $\alpha$ van't hoff factor
$FeCl _{3}      ,  i=4$
$BaCl _{2}       ,  i=3$
$NaCl   ,    i=2$
so  $FeCl _{3}$  has higher value of $i$
so it has Highest BP.

The ability of the particles of a gas or liquid to move out and fill up all available space is called.

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

  1. Melting

  2. Transfusion

  3. Evaporation

  4. Diffusion

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Correct Option: D
Explanation:

Diffusion refers to a process by which molecules intermingle as a result of their kinetic energy of random motion. Molecules of gases are in constant motion and make numerous collisions with the partition.