Tag: chemistry

Questions Related to chemistry

Which liquid has maximum surface tension?

chemistry materials liquid crystals liquid state the liquid state

  1. Water

  2. Alcohol

  3. Ammonia

  4. Glycerol

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Correct Option: A
Explanation:
Tension of the surface film of a liquid caused by attraction of the particles in the surface layer by the bulk of the liquid which minimize surface area.
$\bullet $  Water $=72.86$ $nN/m$
$\bullet$  Ethanol (Alcohol) $=22.10$ $nN/m$
$\bullet$  Glycerol $=64.00$ $nN/m$
Ans :- Option A

When ethanol mixes in cyclohexane reduces the intermolecular forces between ethanol molecule. In this, liquid pair shows:

chemistry materials liquid crystals liquid state the liquid state

  1. ${ \Delta H } _{ mix }>0$

  2. ${ \Delta V } _{ mix }<0$

  3. ${ \Delta G } _{ mix }<0$

  4. ${ \Delta H } _{ mix }=0$

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Correct Option: A
Explanation:
On adding cyclohexane to ethanol . Its molecules get in between the molecules of ethanol thus breaking the hydrogen bonds and reducing ethanol - ethanol interaction .
Thus will increase the vapour pressure of the solution and result in positive deviation from Rouault's law.

With increase in temperature, the fluidity of liquids 

chemistry materials liquid crystals liquid state the liquid state

  1. increases

  2. decreases

  3. remains constant

  4. may increase or decrease

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Correct Option: A

A liquid of density $1.07\ g/ml$ is filled in the barometer, in place of mercury. What should be the length of liquid column, if another barometer filled with mercury, is measuring $75\ cm$ pressure?

chemistry materials liquid crystals liquid state the liquid state

  1. $75\ cm$

  2. $600\ cm$

  3. $9.375\ cm$

  4. $6000\ cm$

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Correct Option: B

A beaker is filled with a liquid of density $\rho $ upto a height pressure on the walls is :

chemistry materials liquid crystals liquid state the liquid state

  1. 0

  2. $h \rho g $

  3. $h \rho g/2 $

  4. $2 h \rho g $

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Correct Option: C

The latent heat of vaporisation of water is:

chemistry materials liquid crystals liquid state the liquid state

  1. $2.25\times 10^6 J/kg$

  2. $2.25\times 10^8 J/kg$

  3. $2.25\times 10^4 J/kg$

  4. $2.25\times 10^{-6} J/kg$

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Correct Option: A
Explanation:

The heat of fusion for water at 0 °C is approximately 334 joules (79.7 calories) per gram, and the heat of vaporization at 100 °C is about 2,250 joules (533 calories) per gram or $2.25 *10^6$ J/kg.

The boiling point of a liquid with the increase of pressure,  ______________.

chemistry materials liquid crystals liquid state the liquid state

  1. decreases

  2. increases

  3. remains constant

  4. changes according to the weather

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Correct Option: B
Explanation:

Since a liquid vaporises when molecules moves faster and farther apart but while increasing pressure, we apply an external force to hold molecules closer to each other. Hence, molecules will require more energy to overcome this resistance thus this increases boiling point of liquid. Hence, the boiling point of a liquid with the increase of pressure, increases.

Which tool allows liquids to be swirled with a low risk of spilling?

chemistry materials liquid crystals liquid state the liquid state

  1. Crucible

  2. Evaporating dish

  3. Tonds

  4. Erlenmeyer flask

  5. Mortar and pestle

Show answer
Correct Option: D
Explanation:

Erlenmeyer flask $\rightarrow$ 

It is used as a container for liquids. Its Shape makes it easy and safe to swirl liquids without spilling, making them ideal for titration. It cannot be used to measure the volume of liquid because its shape makes it difficult to make accurate readings.
Hence the required answer is (C) Erlenmeyer flask.

Most elements are solids at 25$^o$C and 1 atm pressure, the exception being the 11 elements that are gases and 2 that are liquids. What 2 elements are liquids?

chemistry materials liquid crystals liquid state the liquid state

  1. Hg and Br

  2. Hg and I

  3. Ag and Kr

  4. Au and Kr

  5. Pt and Co

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Correct Option: A
Explanation:

At room temperature, that is $25^o C$ and $1$atm, Mercury and Bromine both exist as liquids. Hence option A gives the correct pair.

Iodine, Silver, Platinum, Cobalt are all solid at room temperature. Whereas, Krypton is a gas at room temperature.                                            

With increase in temperature, viscosity and surface tension of a liquid respectively:

chemistry materials liquid crystals liquid state the liquid state

  1. Decrease, decrease

  2. Increase, increase

  3. Increase, decrease

  4. Decrease, increase

Show answer
Correct Option: A
Explanation:
Temperature is increased.
1) As the temperature of a liquid increases,the movement of its molecule increases,which disturbs the imbalanced forces on the surface of liquid.thus the barrier of tightly bound molecules weakens thereby,Surface tension decreases.
2) As the temperature of a liquid increases,the energy of its molecules increases which increases the movement of molecules.so the liquid becomes more fluid.thus viscosity of liquid decreases.