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D) U – shaped valley

Answer is (B) Stack

A glacier erodes through a process called Abrasion

(C) V – shaped valleys

If mean solar day is assumed as standard time and it is divided into 24 equal parts then 1 day = 24 hours.

Similarly, if one hour is divided into 60 equal minutes and one minutes is divided into 60 equal seconds, then 

1 hour = 60 minutes

1 minute = 60 seconds

Similarly, you will find that 1 hour has 3600 seconds and 1 day has 86400 seconds.

(D) Narcondem – Tanzania

Erosion is the process by which soil and rock are removed from the earth’s surface by exogenic processes such as wind or water flow, and then transported and sdeposited on their locations while erosion is a natural process. Human activities have increased by 10 – 40 times the rate of which erosion is occuring globally.

Igneous rocks: The hard rocks formed after the cooling of the molten material from volcanoes.

Answer is (A) 1/5th

Sedimentary rocks: The debris is transported by rivers to the sea, where layer after layer is accumulated in the bottom and over time get transformed into sedimentary rocks.

(i) (C) Angel

(ii) (B) Tugela

(iii) (A) Jog

(iv) (B) Sharavathi

(v) (D) 947 mts

(vi) (A) Jerosoppa

(vii) (B) 253 mts

(viii) (A) 979 mts

1. False 

2. True 

3. True

1. False 

2. False 

3. True 

4. False 

5. True

(C) Both A & B

(A) ‘V’ shaped valleys

Similarities : 

1. They carry something when they flow across the two landforms. 

2. They have streams in both the areas. 3. They change the surface of the earth. 

Differences

From the mountains to delta, a river does not just flow – it changes the surface of the earth. 

It cuts rocks, moves boulders, and deposits sediments. 

It constantly attempts to carve away all the mountains in its path. 

The goal of the river is to create a wide, flat valley which it can flow smoothly towards the ocean. 

That is the relation between the mountains and plains.

i. C) Kashmir

ii. B) Godavari River

iii. A) Colarado

A head land cutting out into the sea is cape

(A) Ox-bow lake

The erosion and deposition of sea waves give rise to coastal landforms such as ‘sea arches, stacks, capes, and bays.’

As a result of the deposition the river changes its course and cuts new path, changes its course constantly, and forms meander and ox-bow lakes subsequently.

To identify the produced gas, lighted matchstick should be brought near the gas. If match stick burns with pop sound, it indicates the evolution of Hydrogen gas. 

M+ 2NaOH → Na₂MO₂+ H₂ 

With HCl 

M+ 2HCl  → 2MCl₂+H₂

The answer is (b)

Copper ions are dispersed from positively charged anode and deposited on negatively charged cathode.

Because it is vacuum packed.

Impure metal is kept as anode, and a thin strip of pure metal is kept as cathode. The pure metal content present in anode is dissolved into the electrolyte and the same amount of copper gets deposited in cathode.

(a) A n atom of Y a ccepts 2 electrons to achieve the nearest inert gas electron arrangement

(2, 8, 8).

(b) Argon

1. after
2. to
3. in
4. at
5. by
6. of
7. of
8. for
9. to
10. on account of
11. inspite of
12. in favour of
13. to
14. into
15. with

(a) An atom of X loses 2 electrons to attain the nearest gas electron configuration (2,8).

(b) Neon

In electrolytic reduction of NaCl, metal is deposited at the cathode and chlorine is liberated at the anode. 

Sodium being electropositive in nature gets attracted to the negative electrode cathode and chlorine being electronegative in nature gets attracted to positive electrode anode.

There was a strange change in her behaviour. She was over-excited. She celebrated the arrival of her grandson. She collected all the women of the neighbourhood. For hours she continued singing and beating the drum. She had to be persuaded to stop to avoid overstraining. Perhaps it was the first time that she didn’t pray.

A person came to buy some rice. Subbiah refused to give him any. He said that he had some other business. But then he agreed to give the rice, but only half a seer for eight annas.

(d) acetyl salicylic acid

The metallic oxide of the form E₂O₃ is Iron [III] Oxide. Iron reacts with chlorine to form different Iron [II] Chloride and Iron [III] Chloride. The ore of Iron that is Fe₂O₃ Haematite does not react with water.

So the correct answer is d

(a) antagonists

The atomic number of sodium is 11, so its electronic configuration is 2,8,1. Sodium atom has only 1 electron in its outermost shell. So, the sodium atom donates one electron (to a chlorine atom) and forms a sodium ion, Na + . The atomic number of chlorine is 17, so its electronic configuration is 2,8,7. Chlorine atom has 7 electrons in its outermost shell and needs 1 more electron to achieve the stable 8-electron inert gas configuration. So, a chlorine atom takes one electron (from the sodium atom) and forms a negatively charged chloride ion, Cl- This type of bonding is called ionic bonding.

(a) (i) 2,8,1 (ii) 2,6

(b) (i) 1 (ii) 6

(c) I onic compounds are usually hard because their oppositely charged ions attract one another strongly and form a regular crystal structure.

(d) Although solid ionic compounds are made up of ions but they do not conduct electricity in solid state. This is because in the solid ionic compound the ions are held together in fixed positions by strong electrostatic forces and cannot move freely. However, when we dissolve the ionic solid in water or melt it, the crystal structure is broken down and ions become free to move and conduct electricity. Thus, an aqueous solution of an ionic compound conducts electricity because there are plenty of free ions in the solution which are able to conduct electric current.

(a) acetylsalicylic acid

a) Magnessium Nitride (Mg₃N₂) 

b) Lithium Oxide( Li₂O) 

c) Aluminium Chloride( AlCl₃) 

d) Potassium Oxide ( K₂O)

Formula of chloride of element X is XCl

Formula of chloride of element Y is YCl 4

The properties of two chlorides will be different because XCl is an i onic chloride whereas YCl₄ is a covalent chloride.

(i) Ionic bonding.

(ii) Covalent bonding.

(iii) Covalent bonding.

(a) There are some elements in group 18 of the periodic table which do not combine with other elements. These elements are helium, neon, argon, krypton, xenon and radon . They are known as noble gases or inert gases because they are unreactive.

If we look at the electronic configuration of noble gases, we would notice that except helium, all other inert gases have 8 electrons (helium has 2) in their outermost shells. This is considered to be the most stable arrangement of electrons.

(b) Atoms form chemical bonds to achieve stability by acquiring the inert gas electron configuration.

Multiple Covalent Bonds

The covalent bonds developed due to mutual sharing of more than one pair of electrons, are termed 'multiple covalent bonds'. 

These are:

Double covalent bond

The bond formed between two atoms due to the sharing of two electron-pairs is called a double covalent bond or simply a double bond. It is denoted by two small horizontal lines (=) drawn between the two atoms, e.g., O = O, O = C = O etc.

Triple covalent bond

Bond formed due to the sharing of three electron pairs is called a triple covalent bond or simply a triple bond. Three small horizontal lines between the two atoms denote a triple bond e.g., N ≡ N, and H - C ≡ C - H (acetylene).

Ionic compounds: Sodium chloride, Ammoniu m chloride, Magnesium chloride. 

Covalent compounds: Urea, Cane sugar, Hy drogen chloride, 

Carbon tetrachloride, Ammonia, Alcohol

(a) Mg ₃ N ₂

(b) Li ₂ O

(c) AlCl ₃

(d) KH

(c) all cis – conflguration

(i) Hydrog en

(ii) Oxygen

(iii) Nitrogen

(iv) Sodium chloride

(a) Ionic compounds conduct electricity in solution because they are made up of electrically charged ions but covalent compounds are made u p of electrically neutral molecules so they do not conduct electricity.

(b) Conduct electricity: MgCl 2 , NaCl, Na 2 S (Ionic compounds)

Do not con duct electricity: CCl 4 , CS 2 ( Covalent compounds) .

Common salt is an ionic compound containing ionic bonds whereas cane sugar is a covalent compound containing covalent bonds. Since, ionic compounds conduct electricity and covalent compounds do not, hence common salt is a good conductor of electricity and cane sugar is a non-conductor of electricity.

(a) polyamide

Sorbitol. It is a sugar substituent where as others are antioxidants