Are you Looking for FSC 1st year Chemistry Chapter 4 Short Questions Notes? In this post, I am sharing 11th Class Chemistry Chapter 4 Liquids and Solids Short Questions with Answers for FSC part 1 students. This is the 4th Chapter in the Chemistry 1st Year book. You can get books of all science subjects by going here.
I have already shared FSC Part 1 Chemistry All Chapters Notes for students. Chemistry is a very important subject for FSC students who are looking forward to adopting the medical field as their profession. Good marks in Chemistry can help them to get admission to medical colleges.
11th Class Chemistry Chapter 4 Liquids and Solids short Question Answers
Relevant Notes of this Chapter
- 1st Year Chemistry Chapter 4 MCQs
- Class 11 Chemistry Chapter 4 Solved Exercise
- Chemistry Class 11 Chapter 4 Long Questions and Notes
Short Questions of 1st Year Chemistry with Answers
Hereunder I am sharing some important Questions and Answers to this chapter. However, for comprehensive Questions and Answers, you should see the above PDF file.
Q. What is Polarizability?
Ans. “Polarizability is the quantitative measurement of the extent to which the electronic cloud can be polarized or disturbed.”
When the electronic cloud is distorted, temporary poles are created in the molecule. With the increase in the atomic no. of the elements down the group, the outermost electrons move away from the nuclei and the distortion of the electronic cloud become more and more easy. So, the polarizability of these atoms go on increasing. This increased distortion of electronic cloud creates stronger London forces and hence the boiling points are increased down the group.
Q. HF is a Weaker Acid than HCI, HBr and HI. Justify: (Gujranwala Board 2006, Lahore Board 2009)
Ans. In HF, the molecules are join with each other in a zig-zag manner due to hydrogen bonding.
The exceptional, low acidic strength of HF molecules as compared to HCI, HBr and HI is due to strong hydrogen bonding. In the zig-zag structure of HF, the partially positive hydrogen is entrapped between two highly electronegative fluorine atoms. So, it is very difficult to ionize the hydrogen from HF molecules. Hence HF is a weaker acid that other halogen acids in which no hydrogen bonding is present.
Q. Evaporation causes cooling. Give reason. (Lahore Board 2005 and 2006)
Ans. Evaporation Causes Cooling: Evaporation causes cooling, the reason is that the high energy molecules leave the surface of the liquid during evaporation, thus leaving behind the low energy molecules. As a result, the average kinetic energy of the liquid molecules decreases and hence the temperature of the liquid falls. Now heat moves from the surrounding to the liquid and therefore the temperature of the surrounding also falls. Therefore, we can say, evaporation cause cooling.
Q. One feel a sense of cooling under the fan after the bath? (Gujranwala Board 2008)
Ans. After taking a bath a thin layer of water is present on the body. When a person stands under the fan after a bath, the water molecules start evaporating from the surface of the body. The rate of evaporation is also increased due to wind pressure. These evaporating water molecules absorb energy from the surface of the body. Hence, the temperature of the body falls and a person feels a sense of cooling.
Q. Why temperature remains constant during boiling a liquid? (Gujranwala Board 2007)
Ans. When a liquid is heated, the kinetic energy of its molecules also increases. Since kinetic energy is directly proportional to absolute temperature, the temperature of the liquid also increases.
At the boiling point of a liquid, the kinetic energy of the liquid molecules become maximum and hence further heating at this stage will note increase the temperature, rather this heat will be utilized to break the intermolecular forces and convert the liquid into vapours.
You should also see 1st Year Chemistry Notes all chapters. I have taken these notes from Azeem Academy Notes. You can request any educational notes in our comment section. Like our Facebook Page and Subscribe to our Youtube Channel for more educational notes.
