Carbon and its Compounds: Class 10 Science Q&A
18 free answers on Carbon and its Compounds (Science) for Class 10 students, across CBSE, ICSE and State boards. Includes questions such as “Explain the mechanism of the cleaning action of soaps.”, “What change will you observe if you test soap with litmus paper (red and blue)?”, “Explain the formation of scum when hard water is treated with soap.”
Question & Answer
Questions
- ScienceClass 10CBSE
Explain the mechanism of the cleaning action of soaps.
Solution: There are so many impurities and dirt mixed in water, and most of all, the dirt does not dissolve in the water. Soap molecules are a combination of salts such as sodium or potassium. The molecules are of a long chain of carboxylic acids. So, when the carbon chain is dissolved in oil, and the ionic end is dissolved in the water, the soap starts cleansing and trapping the dirt. When this happens, the soap molecules form structures called micelles that are used for capturi
- ScienceClass 10CBSE
Give a test that can be used to differentiate between saturated and unsaturated hydrocarbons.
Solution: The bromine water test is used to differentiate between the unsaturated compounds (like alkenes and alkynes) and the saturated compounds. For this purpose, bromine is used in the form of bromine water. A solution of bromine in water is called bromine water. Bromine water has a red-brown colour due to the presence of bromine in it. When bromine water is added to an unsaturated compound, then bromine gets added to the unsaturated compound, and the red-brown colour of brom
- ScienceClass 10CBSE
Which of the following hydrocarbons undergo addition reactions: C2H6, C3H8, C3H6, C2H2 and CH4?
Solution: Unsaturated hydrocarbons undergo addition reactions. C3H6 and C2H2 are unsaturated hydrocarbons which undergo addition reactions.
- ScienceClass 10CBSE
What change will you observe if you test soap with litmus paper (red and blue)?
Solution: When soap is dissolved in water due to the formation of alkaline NaOH or KOH, the solution is alkaline. The solution changes the colour of the red litmus to blue, but in the soap solution, the blue litmus remains blue.
- ScienceClass 10CBSE
Explain the formation of scum when hard water is treated with soap.
Solution: Scum is produced from the reaction of hard water with soap. Calcium and magnesium present in the hard water form an insoluble precipitate called scum.
- ScienceClass 10CBSE
Why are carbon and its compounds used as fuels for most applications?
Solution: Carbon and its compounds are used as fuels for most applications because they have high calorific values and give out a lot of energy. Most of carbon compounds give a lot of heat and light when burnt in the air.
- ScienceClass 10CBSE
Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents, such as ethanol also?
Micelle formation takes place because of the dirt particles in water and clean water. There are two mediums that are involved: one is pure water, and the other is dirt, also called impurities. The soap also has two mediums: (i) organic tail (ii) ionic head So the organic tail mixes and dissolves with the dirt, whereas the oil or grease and ionic head dissolve and mix with the water. Therefore, when the material
- ScienceClass 10CBSE
How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?
Ethanol Ethanoic acid It does not react with sodium hydrogen carbonate Bubbles and fizzes with sodium hydrogen carbonate A good smell Smells like vinegar No action in litmus paper<
- ScienceClass 10CBSE
What is a homologous series? Explain with an example.
A homologous series is a series of compounds which has the same functional group. This also contains a similar general formula and chemical properties. Since there is a change in the physical properties, we can say that there would be an increase in molecular size and mass. For example, methane, ethane, propane, butane, etc., are all part of the alkane homologous series. The general formula of this series is CnH2n+2. Methane CH4</sub
- ScienceClass 10CBSE
Explain the nature of the covalent bond using the bond formation in CH3Cl.
Solution: Carbon can neither lose 4 electrons nor gain four electrons as these processes make the system unstable due to the 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
- ScienceClass 10CBSE
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
Answer: (b) the fuel is not burning completely Solution: While cooking, if the bottom of the vessel is getting blackened on the outside indicates that the fuel is not burning completely.
- ScienceClass 10CBSE
Butanone is a four-carbon compound with the functional group (a) carboxylic acid (b) aldehyde (c) ketone (d) alcohol
Answer: (c) ketone
- ScienceClass 10CBSE
Ethane, with the molecular formula C2H6, has (a) 6 covalent bonds (b) 7 covalent bonds (c) 8 covalent bonds (d) 9 covalent bonds
Answer: (b) 7 covalent bonds Solution: Ethane, with the molecular formula C2H6, has 7 covalent bonds.
- ScienceClass 10CBSE
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?
Solution: Agitation is necessary to get clean clothes as it aids soap micelles to trap the oil, grease or any other impurities that have to be removed. When they are being beaten or agitated, the particles are removed from the clothes’ surfaces and go into the water, thus cleaning the clothes.
- ScienceClass 10CBSE
Would you be able to check if water is hard by using a detergent?
Solution: It is not possible to check if water is hard by using a detergent because detergents are salts of ammonium or sulphonates of long-chain carboxylic acids. Unlike soaps, they do not react with calcium and magnesium to distinguish the nature of water.
- ScienceClass 10CBSE
. What are oxidising agents?
Solution: Oxidising agents are those compounds which either remove hydrogen or add oxygen to a compound. For example, halogens, potassium nitrate, and nitric acid.
- ScienceClass 10CBSE
How would you distinguish experimentally between an alcohol and a carboxylic acid?
Solution: In reaction with sodium carbonate, carboxylic acids produce carbon dioxide gas which turns lime water milky, whereas alcohols do not give this reaction. This experiment can be used to distinguish alcohol and carboxylic acid. The reaction of the carboxylic acid with sodium carbonate: 2CH3COOH + Na2CO3 → 2CH3COONa + H2O + CO2
- ScienceClass 10CBSE
. A mixture of oxygen and ethyne is burnt for welding. Can you tell why a mixture of ethyne and air is not used?
Solution: A mixture of oxygen and ethyne is burnt for welding instead of a mixture of ethyne and air because the production of heat is very important for welding metals. When oxygen and ethyne are burnt, it burns completely and produces a higher temperature than air and ethyne. Oxygen and ethyne produce a very hot blue flame, but the mixture of air and ethyne gives out a sooty flame which means that there are unburnt particles, resulting in lesser heat.