Q1. What would be the electron dot structure of carbon dioxide, which has the formula CO2?
Q2. What would be the electron dot structure of a molecule of sulphur, which is made up of eight atoms of sulphur? (Hint - the eight atoms of sulphur are joined together in the form of a ring.)
Ans: In S8, the atoms are joined together in the form of a ring.
Electron Dot Structure of S8
Q1. How many structural isomers can you draw for pentane?
Ans: We can draw three structural isomers of pentane (C5H12).
Q2. What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?
Ans: The two features of carbon that give rise to a large number of compounds are as follows:
Q3. What will be the formula and electron dot structure of cyclopentane?
Ans: The formula of cyclopentane is C5H10.
Q4. Draw the structures for the following compounds.
(a) Ethanoic acid
Are structural isomers possible for bromopentane?
Yes, the structural isomers of bromopentane are possible by changing the bromine position and branching in the parent carbon chain.
Structural Isomers of Bromopentane
Q5. How would you name the following compounds?
(ii) Methanal (formaldehyde)
Q1. Why is the conversion of ethanol to ethanoic acid an oxidation reaction?
Since the conversion of ethanol to ethanoic acid involves the addition of oxygen to ethanol, therefore it is an oxidation reaction.
Q2. A mixture of oxygen and ethyne is burnt for welding. Can you tell why a mixture of ethyne and air is not used?
Q2. What are oxidising agents? Give an example.
Ans: Those substances that give oxygen or replace hydrogen on reaction with other compounds are known as oxidising agents, such as potassium permanganate (KMnO4).
Q2. People use a variety of methods to wash clothes. Usually, after adding the soap, they 'beat' the clothes on a stone, or beat it with a paddle, scrub with a brush, or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes?
Q1. Ethane, with the molecular formula C2H6, has
(a) 6 covalent bonds
(b) 7 covalent bonds
(c) 8 covalent bonds
(d) 9 covalent bonds
The structural formula for ethane is:
So, it has 7 covalent bonds.
Q2. Butanone is a four-carbon compound with the functional group
(a) Carboxylic acid
Solution: Butanone has the formula CH3COCH2CH3. Thus, it has ketone as a functional group. Option (c) is correct.
Q3. While cooking, if the bottom of the vessel is getting blackened on the outside, it means that
(a) The food is not cooked completely.
(b) The fuel is not burning completely.
(c) The fuel is wet.
(d) The fuel is burning completely.
Solution: This means that the fuel is not burning completely, and unburnt carbon particles get deposited on the bottom of the vessel, making it black.
Q4. Explain the nature of the covalent bond using the bond formation in CH3Cl.
Ans: Carbon can neither lose 4 electrons nor do gain four electrons as these process make the system unstable due to requirement of extra energy. Therefore CH3Cl completes its octet configuration by sharing its 4 electrons with carbon atoms or with atoms of other elements. Hence the bonding that exists in CH3Cl is a covalent bonding.
Here, carbon requires 4 electrons to complete its octet, while each hydrogen atom requires one electron to complete its duplet. Also, chlorine requires an electron to complete the octet. Therefore, all of these share the electrons and as a result, carbon forms 3 bonds with hydrogen and one with chlorine.
Q5. Draw the electron dot structures for
(i) Ethanoic acid
Q6. What is a homologous series? Explain with an example.
Q7. How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?
(i) Difference on the physical basis
(ii) Difference on the chemical basis
Q8. Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?
Q9. Why are carbon and its compounds used as fuels for most applications?
Ans: During the process of combustion of carbon and its compounds, a large amount of heat and light is released, i.e., They have high calorific value, and because of this, carbon and its compounds are used as fuels.
Q10. Explain the formation of scum when hard water is treated with soap.
Q11. What change will you observe if you test soap with litmus paper (red and blue)?
Ans: As a soap solution is basic in nature, it will turn red litmus paper into blue, but it will not affect blue litmus paper.
Q12. What is hydrogenation? What is its industrial application?
Q13. Which of the following hydrocarbons undergo addition reactions:
C2, H6, C3H8, C3H6, C2H2, and CH4.
Ans: Unsaturated hydrocarbons undergo addition reactions. Being unsaturated hydrocarbons, C3H6, and C2H2 will undergo addition reactions.
Q14. Give a test that can be used to differentiate chemically between butter and cooking oil.
Q15. Explain the mechanism of the cleaning action of soaps.