Download App

Science Answer the questions.[Che-3M]

Carbon and its Compounds · CBSE STD 10 (CBSE - English Medium). 22 questions.

Questions

Answer the questions.[Che-3M]

🎯

Test yourself on this topic

22 questions · timed · auto-graded

Question 13 Marks
Write the names of the following functional groups:
  1. $-\text{CHO}$
  2. $-\text{OH}$
  3. $-\text{COOH}$
  4.  

  1. $-\text{X}$
Answer
  1. Aldehyde group.
  2. Alcohol group.
  3. Carboxylic acid group.
  4. Ketone group.
  5. Halo group.
View full question & answer→
Question 23 Marks
Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents like ethanol also?
Answer

Soap are sodium or potassium salts of long-chain carboxylic acids. When soap is added to the water, the hydrophilic end (acid end) will align along the surface of water and the hydrophobic tail (carbon chain) remains out of water. When a soap is dissolved in water, it forms a colloidal suspension in water in which the soap molecules cluster together to form spherical aggregates called micelles. In a soap micelle, soap molecules are arranged radially with hydrocarbon ends directed towards the centre and ionic ends directed outwards.

No, micelle will not be formed in other solvents such as ethanol because hydrocarbon chains of soap molecules are soluble in organic solvents like ethanol.

View full question & answer→
Question 33 Marks
What would be observed on adding a 5% alkaline potassium permanganate solution drop by drop to some warm ethanol in a test-tube? Write the name of the compound formed during the chemical reaction. Also write chemical equation of the reaction which takes place.
Answer
On adding 5% alkaline potassium permanganate solution drop by drop to some warm ethanol, we would observe that the purple color of potassium permanganate starts disappearing; the product formed by this process; ethanoic acid can turn blue litmus red.
$\text{CH}_3\text{CH}_2\text{OH}+2[\text{O}]\xrightarrow[{\text{or}\ \text{acidified}\text{K}_2\text{Cr}_2}\text{O}_7]{{ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{Alkaline}\text{KmnO}_4;\text{Heat}}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }\text{CH}_3\text{COOH}+\text{H}_2\text{O}$
View full question & answer→
Question 43 Marks
What makes the candle flame yellow and luminous?
Answer
When a candle is lighted, the wax melts, rises up the wick and gets converted into vapours. In a candle, there is no provision for the proper mixing of oxygen (of air) for burning wax vapours. So, the wax vapours bum in an insufficient supply of oxygen (of air) which leads to incomplete combustion of wax. This incomplete combustion of wax produces small unburnt carbon particles. These solid carbon particles rise in the flame, get heated and glow to give out yellowish light. This makes the candle flame yellow and luminous.
View full question & answer→
Question 53 Marks
What is meant by denatured alcohol? What is the need to denature alcohol?
Answer
Denatured alcohol is ethyl alcohol which has been made unfit for drinking purposes by adding small amounts of poisonous substances like methanol, pyridine, copper sulphate etc. This is done to prevent the misuse of industrial alcohol for drinking purposes or black marketing (as it is supplied duty free for industrial purposes by the government).
View full question & answer→
Question 63 Marks
What is a soap? Name one soap.
Answer
A soap is the sodium salt (or potassium salt) of a long chain carboxylic acid (fatty acid) which has cleansing properties in water.
Example: Sodium stearate, C17H35COO-NA+
View full question & answer→
Question 73 Marks
What is a homologous series? Explain with an example.
Answer
Homologous series is a group of organic compounds having similar structures and similar chemical properties in which the successive compounds differ by CH2 group.
Example of Homologous series: All the alkanes have similar structures with single covalent bonds and show similar chemical properties, so they can be grouped together in the form of a homologous series.
Homologous series of alkanes: Methane- CH4, Ethane- C2H6, Propane- C3H8, Butane- C4H10, Pentane- C5H12.
View full question & answer→
Question 83 Marks
Three organic compounds A, B and C have the following molecular formulae:
$\text{A} \ \ \text{C}_4\text{H}_8\text{O}_2$
$\text{B} \ \ \text{C}_4\text{H}_{10}\text{O}$
$\text{C} \ \ \text{C}_4\text{H}_8\text{O}$
  1. Which compound contains an alcohol group? Write its name and structural formula.
  2. Which compound contains a carboxyl group? Write its name and structural formula.
  3. Which molecular formula can represent an aldehyde as well as a ketone? Write the names and structural formulae of the aldehyde and ketone represented by this molecular formula.
Answer
  1. The organic compound 'B' comprises an alcohol group. Butanol is the name of the compound, and its formula is C4H9OH.

$ \ \ \ \ \ \ \ \ \text{H} \ \ \ \ \ \text{H} \ \ \ \ \ \text{H} \ \ \ \ \ \text{H}\\ \ \ \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \text{|}\\\text{H}-\text{C}-\text{C}-\text{C}-\text{C}-\text{OH}\\ \ \ \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \text{|}\\ \ \ \ \ \ \ \ \ \text{H} \ \ \ \ \ \text{H} \ \ \ \ \ \text{H} \ \ \ \ \text{H}$

  1. The organic compound 'A' contains a carboxyl group. The name of the acid is butanoic acid, and its formula is C3H7COOH.

$\ \ \ \ \ \ \ \ \text{H} \ \ \ \ \ \text{H} \ \ \ \ \ \ \text{H} \ \ \ \ \ \text{O}\\ \ \ \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \text{||}\\\text{H}-\text{C}-\text{C}-\text{C}-\text{C}-\text{OH}\\ \ \ \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \ \text{|}\\ \ \ \ \ \ \ \ \ \text{H} \ \ \ \ \text{H} \ \ \ \ \ \ \text{H}$

  1. Compound 'C' (C4H8O), represents the molecular formula of an aldehydes as well as a ketone. The aldehyde represented by this formula is butanal (C3H7CHO).

$ \ \ \ \ \ \ \ \ \text{H} \ \ \ \ \ \text{H} \ \ \ \ \ \text{H} \ \ \ \ \ \text{O}\\ \ \ \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \text{||}\\\text{H}-\text{C}-\text{C}-\text{C}-\text{C}-\text{H}\\ \ \ \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{|}\\ \ \ \ \ \ \ \ \ \text{H} \ \ \ \ \ \text{H} \ \ \ \ \ \text{H}\\ \ \ \ \ \ \ \ \ \ \ \ \text{Butanal}$ $ \ \ \ \ \ \ \ \ \text{H} \ \ \ \ \ \text{O} \ \ \ \ \ \text{H} \ \ \ \ \ \text{H}\\ \ \ \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{||} \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{|}\\\text{H}-\text{C}-\text{C}-\text{C}-\text{C}-\text{H}\\ \ \ \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{|} \ \ \ \ \ \ \ \text{|}\\ \ \ \ \ \ \ \ \ \text{H} \ \ \ \ \ \text{H} \ \ \ \ \ \text{H}\\ \ \ \ \ \ \ \ \ \ \ \text{Butanone}$

View full question & answer→
Question 93 Marks
Name the reaction which is usually used in the conversion of vegetable oils to fats. Explain the reaction involved in detail. Write a chemical equation to illustrate your answer.
Answer

Catalytic hydrogenation is usually used in conversion of vegetable oils to fats.

Hydrogenation of oils: Vegetable oils are unsaturated fats having double bonds between some of their carbon atoms and can undergo addition reactions. When a vegetable oil (like groundnut oil) is heated with hydrogen in the presence of finely divided nickel as catalyst, then a saturated fat called vegetable ghee (or vanaspati ghee) is formed. This reaction is called hydrogenation of oils and it can be represented as follows:

View full question & answer→
Question 103 Marks
Name the functional group of organic compounds that can be hydrogenated. With the help of a suitable example, explain the process of hydrogenation, mentioning the conditions of the reaction and any one change in physical property with the formation of the product. Name any one natural source of organic compounds that are hydrogenated.
Answer
Alkenes can be hydrogenated.
The addition of hydrogen to an unsaturated hydrocarbon to obtain a saturated hydrocarbon is called hydrogenation.
Example: Ethene reacts with hydrogen in the presence of finely divided nickel as catalyst to form ethane. Liquid vegetable oils are hydrogenated into vegetable ghee (solid fat).
$\text{CH}_2=\text{CH}_2+\text{H}_2\xrightarrow[ {\text{Heat}}]{{ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{NiCatalyst}}\ \ \ \ \ \ \ \ \ \ \ \ \ }\text{CH}_3-\text{CH}_3$
View full question & answer→
Question 113 Marks
Giving their structures, state the number of single bonds, double bonds and triple bonds in the following compounds:
  1. Ethyne.
  2. Ethene.
  3. Benzene.
Answer
Ethyne: Single bonds: Two; Triple bond: One.

$\text{H}-\text{C}\equiv\text{C}-\text{H}$

Ethene: Single bonds: Four; Double bond: One.

Ethane: Single bonds: Nine; Double bonds: Three.

View full question & answer→
Question 123 Marks
Give reasons for the following observations:
  1. Air holes of a gas burner have to be adjusted when the vessels being heated get blackened by the flame.
  2. Use of synthetic detergents causes pollution of water.
Answer
  1. Air holes of a gas burner have to be adjusted b ecause blackening of vessels show that the air holes of the gas stove are getting blocked and hence the fuel is not burning completely (due to insufficient supply of oxygen).
  2. Some of the detergents (synthetic) are not bio-degradable, that is they cannot be decomposed by micro organisms like bacteria and hence cause water pollution.
View full question & answer→
Question 133 Marks
Explain why, methanol is much more dangerous to drink than ethanol.
Answer
Unlike ethanol, drinking methanol, even in a small quantity can be fatal leading to permanent blindness and even death. Methanol damages the optic nerve causing permanent blindness in a person. This happens because methanol is oxidised to methanal in the liver of a person. This methanal reacts rapidly with the components of the cell causing coagulation of their protoplasm. Due to this, the cells stop functioning normally.
View full question & answer→
Question 143 Marks
Explain why, diamond is hard while graphite is soft (though both are made of carbon atoms).
Answer
A diamond crystal is a giant molecule of carbon atoms. Each carbon atom in the diamond crystal is linked to four other carbon atoms by strong covalent bonds. The four surrounding atoms are at the four vertices of a regular tetrahedron. This rigid structure of diamond makes it a very hard substance.
The structure of graphite is very different from that of diamond. A graphite crystal consists of layers of carbon atoms or sheets of carbon atoms and these layers are held together by weakVan der Waals forces. Due to this sheet like structure, graphite is a comparatively soft substance.
View full question & answer→
Question 153 Marks
Explain the process of preparation of soap in laboratory.
Answer
Soap can be prepared in the laboratory as follows:
  1. Take about 20ml of castor oil (cottonseed oil, linseed oil or soya bean oil) in a beaker.
  2. Add 30ml of 20% sodium hydroxide solution to it.
  3. Heat the mixture with constant stirring till a paste of soap is formed.
  4. Then add 5 to 10 grams of common salt (sodium chloride).
  5. Stir the mixture well and allow it to cool. On cooling the solution, solid soap separates out.
  6. When the soap sets, it can be cut into pieces called ‘soap bars’.
View full question & answer→
Question 163 Marks
Esters are sweet-smelling substances and are used in making perfumes. Describe an activity for the preparation of an ester with the help of a well labelled diagram. Write an equation for the chemical reaction involved in the formation of the ester. Also write the names of all the substances involved in the process of esterification.
Answer
 Activity:

  1. Take 1ml of pure ethanol (absolute alcohol) in a test-tube and add 1ml of glacial ethanoic acid to it. Then add 2 or 3 drops of concentrated sulphuric acid to the mixture.
  2. Warm the test-tube containing above reaction mixture in hot water bath (a beaker containing hot water) for about 5 minutes.
  3. Pour the contents of the test-tube in about 50ml of water taken in another beaker and smell it.
  4. A sweet smell is obtained indicating the formation of an ester.

Reaction:

$\text{CH}_3\text{COOH}+\text{C}_2\text{H}_5\text{OH}\xrightarrow[{}]{{ \ \ \ \ \ \ \ \ \ \ \ \text{Cons}.\text{H}_2\text{SO}_4}\ \ \ \ \ \ \ \ \ \ \ \ \ }\text{CH}_3\text{COOC}_2\text{H}_5+\text{H}_2\text{O}\\\text{Ehanoic}\ \text{acid}\ \ \ \text {Ethanol}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{Ethyl ethanoate}\ \ \ \text{Water}\$\text{Acetic}\ \text{acid})\ \ (\text{Ethyl}\ \text{alcohol})\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ (\text{Ethylacetate}-\text{ester})$

View full question & answer→
Question 173 Marks
Describe the structure of a soap molecule with the help of a diagram.
Answer
A soap molecule has two parts: The long chain organic part and the ionic part containing the -COO-Na+ group. It has to be remembered that this is not an ion, the atoms are all covalently bonded, the electrical charges show how the charges get polarized in the group. A soap molecule has a tadpole like structure shown below:

View full question & answer→
Question 183 Marks
Describe how petroleum was formed in the earth.
Answer
Petroleum oil (and natural gas) was formed by the decomposition of the remains of extremely small plants and animals buried under the sea millions of years ago. It is believed that millions of years ago, the microscopic plants and animals which lived in seas, died. Their bodies sank to the bottom of the sea and were soon covered with mud and sand. The chemical effects of pressure, heat and bacteria, converted the remains of microscopic plants and animals into petroleum oil and natural gas just as they converted forest trees into coal. This conversion took place in the absence of oxygen or air. The petroleum thus formed got trapped between two layers of impervious rocks (non-porous rocks) forming an oil trap.
View full question & answer→
Question 193 Marks
Classify the following compounds as alkanes, alkenes and alkynes:

C2H4, C3H4, C4H8, C5H12, C5H8, C3H8, C6H6

Answer
Alkanes.

C5H12, C3H8

Alkenes.

C2H4, C4H8

Alkynes.

C3H4, C5H8

View full question & answer→
Question 203 Marks
A solid element X has four electrons in the outermost shell of its atom. An allotrope Y of this element is used as a dry lubricant in machinery and also in making pencil leads.
  1. What is element X?
  2. Name the allotrope Y.
  3. State whether allotrope Y is a good conductor or non-conductor of electricity.
  4. Name one use of allotrope Y (other than lubrication and pencil leads)
  5. Name two other allotropes of element X.
Answer
  1. Element X: Carbon.
  2. Allotrope Y: Graphite.
  3. Y is a good conductor of electricity.
  4. Y is used for making graphite electrodes or carbon electrodes in dry cells.
  5. Allotropes of X: Diamond and buckminsterfullerene.
View full question & answer→
Question 213 Marks
An organic acid X is a liquid, which often freezes during winter time in cold countries, having the molecular formula C2H4O2. On warming it with methanol in the presence of a few drops of concentrated sulphuric acid, a compound Y with a sweet smell is formed.
  1. Identify X and Y. Also write their formulae showing the functional group present in them.
  2. Write a chemical equation for the reaction involved.
Answer
  1.  

X is ethanic acid: $\ \ \ \ \ \ \ \ \ \ \ \ \ \text{O}\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{||}\\ \text{CH}_3-\text{C}-\text{OH}$

Y is methyl ethanoate: $\ \ \ \ \ \ \ \ \ \ \ \ \ \text{O}\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{||}\\ \text{CH}_3-\text{C}-\text{O}-\text{CH}_3$

  1. $\text{C}\text{H}_3\text{COOH}+\text{CH}_3\text{OH}\xrightarrow{ \ \ \ \ \text{Conc.}\text{H}_2\text{SO}_4 \ \ \ }\text{CH}_3\text{COOC}\text{H}_3+\text{H}_2\text{O}$
View full question & answer→
Question 223 Marks
A hard material X which is mined from the earth is used as a house hold fuel and also for the generation of electricity at Thermal Power Stations. A soft material Y is also used us a fuel in the form of candles. A gaseous material Z which occurs along with petroleum is increasingly being used as a fuel in running vehicles in its compressed form.
  1. What are materials, X, Y and Z?
  2. When materials X, Y and Z are burned separately:
  1. When material burns by producing a yellow, luminous flame?
  2. Which material ultimately burns without producing a flame?
  3. Which material can burn in a gas stove by producing a blue flame?
Answer
  1. X is coal, Y is wax Z is natural gas.
  2.  
    1. Y (wax).
    2. X (coal).
    3. Z (natural gas).
View full question & answer→
Generate Paper FreeAll Carbon and its Compounds topics
Answer the questions.[Che-3M] - Science STD 10 Questions - Vidyadip