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The general formula of alkenes is C_nH_2n, where ‘n’ is the number of carbon atoms. 

Here, C₂H₄ and C₃H₆ are alkenes (put n=2, 3)

C₂H₆ and C₂H₂ are unsaturated Hydrocarbons. Hence these undergo addition reactions.

CH₄, C₃H₈ and C₅H₁₂; all these are saturated hydrocarbons (Alkanes) and hence will give substitution reactions.

C₂H₄ and C₃H₄ will give addition reactions because these are unsaturated hydrocarbons (Alkene and Alkyne) and unsaturated hydrocarbons give addition reactions.

1. (i) TRUE

2. (iv) All of the above

3. (iii) Both (i) and (ii)

4. (i) TRUE

5. (iv) All of these

(a) Allotropy

Carbon forms large number of compounds because of tetravalency and catenation property. 

Tetravalency – Carbon has valency 4, to attain noble gas configuration carbon share its valence electrons with other elements like hydrogen, chlorine, etc. 

Catenation – Carbon also shows the property of self-linking in which it forms long, branched or cyclic chains to form large number of compounds.

(a) 

(i)-Catenation 

(ii) Tetravalency 

(b) It is because large number of molecular ions of soaps get aggregated and form colloidal solution. Soap has hydrophobic tail (hydrocarbon) which dissolves in hydrocarbon part and hydrophilic part dissolves in water. Ethanol is non-polar solvent therefore micelles are not formed because hydrocarbon part gets attracted towards ethanol and ionic end will not dissolve in alcohol.

(i) Alkene, C_nH_2n e.g., C₂H₄, ethene

(ii) Alkyne, C_nH_2n-2 e.g., C₂H₂, ethyne

(a) Hydrocarbons – A compound of carbon and hydrogen.

(b)

Catenation – Self linking property which leads to long straight chains, branched chains and cyclic chains.

(c) Carbon forms large number of compounds due to

1.  Isomerism – Compound of carbon can exist in more than one structural formula but has same molecular formula.
2. Tetravalency – To acquire noble gas configuration, carbon shares its outer electrons with other elements, thus form covalent bond with other elements.

Saturated house single bonds, unsaturated have multiple bonds.

Some substances are capable of adding oxygen to others. These substances are known as oxidising agents. 

Example: alkaline KMnO₄ and acidified K₂Cr₂O₇.

K₂ Cr₂ O₇ , KMn0₄

False

Animal fats contain saturated fatty acids which are harmful for our health. Vegetable oils on the other hand, contain unsaturated fatty acids which are good for our health.

1. Animal fats have recently been implicated as the cause of heart disease and obesity. So, we are advised not to use animal fats for cooking.

2. Excess animal fat is stored in lipocytes, which expand in size until the fat is used for fuel.

Soaps and detergents make oil and dirt present on the cloth come out into water, thereby making the cloth clean. 

Soap has one polar end and one non-polar end.

1. The polar end is hydrophilic in nature and this end is attracted towards water. 

2. The non-polar end is hydrophobic in nature and it is attracted towards grease or * . ; oil on the cloth, but not attracted towards water. 

3. When soap is dissolved in water, its hydrophobic ends attach themselves to dirt and remove it from the cloth. 

4. The hydrophobic end of the soap molecules move towards the dirt or grease particles. 

5. The hydrophobic ends attach to the dirt particle and try to pull out. 

6. The molecules of soap surround the dirt particle at the centre of the cluster and form a spherical structure called micelle. 

7. These micelles remain suspended in water like particles in a colloidal solution. 

8. The various micelles present in water do not come together to form a precipitate as each micelle repels the other because of the ionion repulsion. 

9. Thus, the dust particles remain trapped in micelles and are easily rinsed away with water. 

10. Hence, soap micelles remove dirt by dissolving it in water.

The magnesium and calcium salt present in hard water react with the soap molecule to form an insoluble product called scum. This scum create difficulty in cleansing action.

Yes, soap can be used for washing clothes in water containing sodium bicarbonate, as sodium ion will not contribute to the hardness of water.

(a) Soap is sodium or potassium: Salt of higher fatty acids such as oleic acid (C₁₇H₃₃COOH), stearic acid (C₁₇H₃₅COOH), palimitic acid (C₁₅H₃₁COOH), etc. A soap is a sodium or potassium salt of long chain fatty acids. Hard water contains salts of calcium and magnesium. On adding soap to water, calcium and magnesium ions present in water displace sodium or potassium ions from the soap molecules forming an insoluble substance called scum. Scum results in wastage of soap. 

(b) Cleansing action of soaps: The oily spot present on clothes is organic in nature and insoluble in water. Therefore, it cannot be removed by only washing with water. When soap is dissolved in water, its hydrophobic ends attach themselves to the oily spot and remove it from the cloth. Then, the molecules of soap arrange themselves in the form of micelle and trap the dirt at the centre of the cluster. These micelles remain suspended in the water. Hence, the oily spots are easily rinsed away by water.

(b) A-2, B-4, C-1, D-3

(d) Li⁺_(aq) < Na⁺_(aq) < K⁺_(aq)

X³⁺, Y²⁺ , Z^- are iso electronic. 

∴ Effective nuclear charge is in the order 

(Z_eff)_Cl^- < (Z_eff)Y_Y²⁺ < (Z_eff)_X³⁺ and hcnce, ionic radii should be in the order r_Z^- > r_Y²⁺ > r_X³⁺ 

∴ The correct values are:

Halogens — group No. 17 

Alkali metals — group No. 1 

Inert gases — group No. 18 

Hydrogen — group No. 1 

He, Ne and Ar are called inert gases because their outermost shell is complete and they do not lose or gain electrons in their outermost shell, hence they have zero valency.

The reason they are inert gases is because they do not bond easily with other elements. They have a full valence of electrons so they don't need any to satisfy their own valence. They are also called noble gases because they are like this.

(i) Li, Na and K are grouped together in the periodic table and belong to group I. They are grouped together because all of them have one electron in their valence shell. Rest of the elements Cl, Br and I are grouped together in the periodic table and belong to group 17.
(ii) The elements of group 1 are called alkali metals because they react with water to liberate H₂ gas and form alkalis. The elements of group 17 are monovalent non-metals. They from acidic oxides and are called halogens.

The elements of group 1 have only one electron in their respective valence shells and thus have a strong tendency to lose this electron. The tendency to lose electrons in turn, depends upon the ionization enthalpy. Since the ionization enthalpy decreases down the group therefore, the reactivity of group 1 elements increases in the same order Li

(d) Be, B, C

Group 1 : Hydrogen. 

Group 16 : Oxygen. 

Group 17 : Chlorine and Bromine.

Answer: (c) Cl^-

(a) Object Data Base Management System

Object oriented model uses small, reusable software known as objects.

Phpmyadmin is the most popular web administration tool.

OOP’s stands for Object Oriented Language.

Columns are otherwise called as attributes.

Composite key is otherwise called as compound key.

(c) Minimal super key

Each super key is called as Candidate key.

A primary key which is a combination of more than one attribute is called a composite primary key.

Various access methods in file system were indexed, random and sequential access.

“A database management system (DBMS) is system software for creating and managing databases. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data”.

TCL stands for Transaction Control Structure.

DQL stands for Data Query Language

DML stands for Data Manipulation Language.

1. The candidate key that is chosen to perform the identification task is called the primary key and any others are Alternate keys. 

2. Every tuple must have, a unique value for its primary key.

To prevent the conflict in database update, the trAnswer:actions are isolated from other user and serialized. This is also known as Degree of Consistency.

Correct Answer is: (c) Language

Correct Answer is: (b) 3

Hierarchical database model uses tree structure.

The famous Hierarchical database model was IMS.