Carbon And Its Compounds - Class 10 Chemistry - Extra Questions

• Combustion is a chemical process whereas respiration is a biological process.
  
• Combustion takes place at high temperature whereas respiration takes place at normal temperature.
• No enzyme is involved in combustion whereas enzymes are involved in respiration.

Ethanol is used in medicines such as tincture iodine, cough syrups, and many tonics.

Carbon in hydrocarbons forms bonds by sharing of electrons.
Carbon forms four covalent bonds by sharing its four valence electrons with four univalent atoms, e.g., hydrogen. After the formation of four bonds, carbon attains the stable electronic configuration of $$2,8$$.

Petrol, diesel, kerosene, acetic acid and ethanol are compounds of carbon.

Following are the main characteristics of carbon atom:

• Valency of carbon atom is $$4$$.
• Carbon can make a single bond, double bond, and triple bond with other atoms.
• It can make linear, branched chains and cyclic compounds by bonding with other carbon atoms and other elements.

In the covalent compounds, molecules are held together by weak inter-molecular forces. So, the temperature required to separate these molecules is low. Hence, they have low melting points.

At least one carbon bond in an unsaturated hydrocarbon is double.

Ethane is a saturated hydrocarbon containing two carbon atoms.

Carbon gets its name from the Latin word "carbo" meaning charcoal or coal.

$$C_{2}H_{5}OH  + CH_{3}COOH \xrightarrow[\Delta]{Con.H_{2}SO_{4}} CH_3COOC_2H_5 + H_2O$$

  The correct answer is slippery.

The answer is a covalent bond.

Carbon has 4 valence electrons. In order to make octet, it shares each of the four electrons with each of the three hydrogen atoms and one chloride atom. Since, bonds are formed because of sharing of electrons, hence these are covalent bonds.

Carbon and its compounds are used as fuels due to following reasons-

• Butter is a saturated compound while cooking oil is an unsaturated compound.
• Unsaturated compounds are oxidized by alkaline potassium permanganate with the disappearance of its pink colour.
• When cooking oil is treated with a few drops of Alkaline $$KMnO_{4}$$ solution the pink colour of $$KMnO_{4}$$ disappears. However pink colour of $$KMnO_{4}$$ does not disappear when treated with butter.

                     

Additional Information

• We can also distinguish chemically between cooking oil and butter by the bromine water test. 

An alkene will turn brown bromine water colourless as the bromine reacts with the carbon-carbon double bond.

Answer: 7

The IUPAC name of ethanol is ethan-1-ol.

Some chemical elements exist in two or more different forms, in the same physical state. These different forms are called allotropes.  
Diamond, graphite and fullerene are different allotropes of carbon.
Graphite is used in ribbons for printing in computes and typewriters and also in lead pencils.

Saturated hydrocarbons contain all $$C-C $$ single bonds whereas unsaturated hydrocarbons contain $$\displaystyle C=C$$ double bond (alkenes) and $$\displaystyle C \equiv C$$ triple bonds (alkynes).

(a) Saturated hydrocarbons: Hydrocarbons in which the carbon atoms are linked to each other by single bonds only are known as saturated hydrocarbons.

Diamond and graphite are well-known allotropes of carbon. In a diamond, the carbon atoms are arranged tetrahedrally. Each carbon atom is attached to four other carbon atoms.  It is a strong, rigid three-dimensional structure that results in an infinite network of atoms. This accounts for the diamond's hardness.

b) Correct series:-

Compound	Series
Ethane	saturated hydrocarbon
Benzene	unsaturated hydrocarbon
Hexane	long-chain saturated hydrocarbon
Methyl alcohol	Hydrocarbon having odd atom

• The bond formed by sharing of electrons between atoms is known as a covalent bond. Molecules of compounds containing such bonds are known as covalent compounds.
• Properties of covalent compounds include:
1. Have low boiling points and melting points.
2. Generally are poor conductors of heat and electricity.
3. Exist as brittle solids.

For example, a water molecule, $$H_2O$$, is formed by the sharing of electrons between hydrogen and oxygen. And another example of a covalent compound is "Carbon dioxide, $$CO_2$$, where carbon and oxygen share electrons.

Name of the given saturated ring compound is cyclobutane. Number of single bonds present are 12.

The structure for ethanoic acid is shown above.

According to periodic table,

Atomic number carbon$$=6$$

Electronic configuration of carbon $$=2,4$$

And Covalent bond is being formed by carbon because of its catenation and tetravalency behaviour.

It shares its electrons with other elements instead of donating or losing.

Some allotropes of carbon are graphite, diamond etc.

(i) 

In graphite, each carbon atom is bonded with three other carbon atoms to form hexagonal rings which join together by weak Van der Waal forces to form layers. Due to the weak force, these layers can slide over each other, and therefore, graphite can be used as a lubricant.

The element whose allotropic form is graphite is Carbon.

$$C_{60}$$ is called buckminsterfullerene.

Graphite is used in pencils.

The element whose one of the allotropic forms is buckminsterfullerene is Carbon. The other allotropic form of Carbon are diamond and graphite.

The form of carbon which is known as black lead is graphite.

The form of carbon that is used as a lubricant at high temperatures is graphite.

The diameter of 1 C atom is $$\displaystyle 0.15 nm = 0.15 \times 10^{-7} cm$$. 

(a) Carbon exhibits the property of catenation therefore element $$A$$ is carbon
(b) Carbon reacts with oxygen and forms carbon dioxide which is used by plants in photosynthesis. Therefore gas $$B$$ is carbon dioxide
(c) Allotrope of carbon which is used as glass cutters is diamond. So, allotrope $$C$$ is diamond
(d) Diamond is also used in making jewellery
(e) Another allotrope of carbon that exists as the spherical molecule is buckminsterfullerene.
(f) Graphite is the only allotrope of carbon that conducts electricity.

Carbon compounds have usually low melting points and boiling points because they are covalent in nature.

(a) Element $$X : Carbon$$
(b) Allotrope $$Y : Graphite$$
(c) $$Y$$ is a good conductor of electricity as its structure contains free electrons which allows for easy conduction of electricity.
(d) $$Y$$ is used for making electrodes in dry cells.
(e) Allotropes of $$X$$: Diamond and Buckminsterfullerene.

Ethanoic acid reacts with sodium hydroxide to give sodium ethanoate and water.

Methane reacts with chlorine in the presence of sunlight to form chloromethane and hydrogen chloride. Here, one hydrogen atom of methane is getting substituted with a chlorine atom. This is why it is a substitution reaction.

$$ CH_{3}COOH +  NaOH\rightarrow \underset{sodium \ ethanoate}{CH_{3}COONa}+H_{2}O $$

Unsaturated carbon compounds do not burn completely and give a flame with unburnt or partially burnt carbon particles. Such a flame has a yellow color and is polluting. It is called a sooty flame. While saturated carbon compounds usually burn completely and give a clear blue flame

Ethanol is harmful to drinking. 

A carbon atom forms a covalent bond with other atoms. In this bond the two atoms share electrons.

Carbon possesses the unique property of combining with other carbon atoms to form long chains. This property is called catenation. The chains can be straight, branched, or closed.

In this reaction, sulphuric acid acts as dehydrating agent and also as catalyst. 
$$CH_3CH_2OH \xrightarrow{conc. \ H_2SO_4} CH_2 = CH_2 + H_2O$$

Methanol is oxidized to methanal in liver. Methanal coagulates the cytoplasm in cells; which kills the cells. Methanal also acts on optic nerves and causes blindness. Thus, intake of even small quantity of methanal can be lethal. 

The evolved is carbon dioxide $$ (CO_{2}) $$. 

The melting point of pure ethanoic acid is 290 K and hence it often freezes in cold climates and forms a colourless, ice-like liquid. This property has given it the name glacial acetic acid.