Explore topic-wise InterviewSolutions in Current Affairs.

The answer is (C) Evaporation, diffusion, expansion of gases

The answer is (B) Gases have a very weak tendency to diffuse

The answer is (D) Solid CO₂

The answer is (A) the melting point is below the room temperature

The answer is (D)

Correct Answer is: (b, d)

Use symmetry arguments. If a p.d. is applied between A and B, the paths ADB and ACB become equivalent, while D and C are at the same potential (and hence can be removed from the circuit).

Correct Answer is: (a)

Correct Answer is: (d) 4R/3

Correct Answer is: (c) 2R/3

(D) All of these

1 mole of atom or ions or molecule or particle contains \(6.0221367 × 10^{23}\) atoms, or ions or molecules or particles respectively.

Hence, option (D) is right answer.

Option : (D) All of these

(a) 3 

(b) One mole of sugar C₁₂H₂₂O₁₁ contains 11 × 6.023 × 10²³ oxygen atoms. = 66.253 × 10²³ = 6.6253 × 10²³ atoms of oxygen 

(c) C₆H₁₂O₆.

When the condensation of the water vapor takes place near the surface, the visibility of the surface or atmosphere becomes less than 1 km, then this form of condensed water vapor is called fog.

The lines which are drawn to join the places of equal rainfall on the map of the world, are called the isohyet lines. By the study of these lines, the distribution of rainfall in the world can be systematically understood. Isohyets prove to be the most useful in showing less and more rainfall across the earth’s surface.

Mass of oxalic acid = 11 g

Mass of solution = Volume × Density

= 500 × 1.1

= 550 g

\(\therefore\) Mass % of oxalic acid =  \(\frac{Mass\,of\,oxalic\,acid}{Mass\,of\,solution}\) x 100

= \(\frac{11}{550}\) x 100 = 2%

2KClO₃(s) \(\overset{\Delta}{\rightarrow}\) 2 KCl(s) + 3O₂(g)

Molar mass of KClO₃ = 39 + 35.5 + 3(16) = 122.5

\(\because\) 245 g KClO₃ produce = 22.4 × 3 L of oxygen

\(\therefore\) 12.25 g KClO₃ will produce = \(\frac{22.4\times3}{24.5}\) x 12.25

= 3.36 L of oxygen.

The formula of calcium carbonate is CaCO₃.

The formula of the compound obtained by the combination of NH4 and Cl well be NH₄Cl

The amount of energy required to remove the most loosely bound electron, the valence electron, of an isolated gaseous atom to form a cation is called ionization energy.

(a) \(2KClO_3\overset{\Delta}{\rightarrow}2KCl+3O_2\uparrow\)

(b) \(BaCl_2+2AgNO_3 \rightarrow 2AgCl\downarrow+Ba(NO_3)_2\)

(c) \(Mg+2HCl\rightarrow MgCl_2+H_2\)

(d) \(2NaOH+Cl_2\rightarrow NaCl+NaOCl+H_2O\)

(c) low ignition temperature and can catch fire easily. 

H₂O has covalent bond.

(A) By giving and taking (exchange) of electrons

Two oxygen atoms may achieve stability by forming covalent bonds with one another. Each oxygen atom has six electrons in its outer shell. To become stable, the two atoms share two pairs of electrons, forming molecular oxygen. When two pairs of electrons are shared (0=0), the bond is called the double covalent bond. Some atoms form triple bonds with one another by sharing three pairs of electrons. For example, nitrogen form a triple covalent bond, by sharing three pairs of electrons with another.

Ionic or Electrovalent bond: Ionic bond is formed between the atoms of the electropositive element and electronegative element. When an electropositive element comes close to the electronegative element, the atoms of electropositive element donates electron from its outermost shell and attains the structure of nearest inert gas and becomes positively charged. The electronegative element accepts electron(s) in outermost shell and attains the electron configuration of nearest inert gas. It becomes negatively charged. These oppositely charged ions bind each other, by a strong electrostatic force known as an electrovalent bond or ionic bond.

Differences between the covalent compound and ionic compound are:

(A) Frankland

The symbolic representation of an actual chemical reaction is called a chemical equation.

The formula which shows the actual number of atoms of the elements present in one molecule of a substance is molecular formula.

A group of symbols of elements which represents one molecule of a substance is called formula.

Example: Formula of water is H₂O

Molecular formula – It is the formula which shows the actual number of atoms of the elements present in one molecule of the substance.

Example: The molecular formula of ammonia gas is NH₃. This shows that one molecule of ammonia gas contains one atom of nitrogen and 3 atoms of hydrogen.

The molecular formula of a metallic chloride is MCI. The molecular formula of its sulphate will be M₂SO₄

Atoms of the metals form cations after losing one or more electrons. When a neutral metal atom will lose electrons, the number of electrons will be less than the protons. As a result, forces of attraction will increase between the positively charged nucleus and electrons and the cloud of electrons will contract. This results in the smaller size of cation than the corresponding atom. Also, when the cation is formed by losim electrons of the outermost shell, it has one shell less than the atom and so its size is smaller.

Radicals: A radical is an atom or group of atoms of the same or different elements carrying either positive or negative charge, which behaves as one unit in a chemical reaction. 

The positively charged ions are called basic radicals, e.g. sodium Nay Ammonium NH₄ .The negatively charged ions are called acid radicals e.g., Nitrate NO₃Oxide, O₂ ; carbonate, CO₃² .

(D) Rutherford

The molecular formula of magnesium nitrate is Mg(NO₃)₂

Valency: Valency is defined as the number of hydrogen atoms which combine directly or indirectly with one atom of an element. 

Example: One atom of nitrogen combines with three atoms of hydrogen to form ammonia gas. So, the valency of nitrogen is 3.

The radical of phosphate among the following radicals is PO₄^3-

When an atom receives electrons, it carries a negative charge. It is called an anion. Energy is released in the formation of the anion.

Phosphate (PO₄) ^-3

Barley is not practiced during ‘Zaid’ season.

Air is a mixture of various gases in a particular ratio. Whenever the ratio of these gases become imbalanced or there is addition of harmful substances, the air is said to be polluted.

Measures to control air pollution: 

1. Industrial areas should be established at a distance away from residential areas. 

2. Automobiles should be fitted with emission control measures. 

3. Trains should be made to run with electric engines. 

4. Minimum use of vehicles should be made. 

5. Destruction of forests should be stopped. 

6. Public should be educated in pollution control measures. 

7. People should be discouraged from burning garbage. 

8. Factories emitting smoke must adopt pollution control measures.

Carbon dioxide, carbon monoxide, smoke, dust, ozone, pollen and microbes, oxides of nitrogen etc.

Health is the state of complete fitness and mental well-being and not merely the absence of disease or infirmity.

According to the WHO health is the state of complete physical ,social ,mental and spritual well being and not merely the absence of disease or infirmity. 

1. Long cancer, 

2. Asthma, 

3. Cough, 

4. Eye infections, 

5. Tuberculosis, 

6. Bird flu etc.

Global warming, depletion of ozone layer, water pollution, air pollution, drought, destruction of forests etc.

Effects of Water Pollution: The effects of water pollution depend upon the nature of pollutants present in water. Pollutants bring about physical and chemical changes that make the water unfit for drinking and also harmful to the organisms present in it. Water is generally polluted in its sources as rivers, tanks, springs etc.

The major sources of water are:

1. Rain Water: Water from the initial two or three rains is polluted due to presence of dust particles in it. After two or three rounds the rain water becomes pure. It was a practice in Rajasthan to collect this water in the tanks to be used for the whole year. This practice of collecting the rain water by different means can solve the problem. 

2. Hand Pump Water: Hand pump water is best for drinking provided it is not heavy and acidic. 

3. Tank-Water: Water is collected in the tanks from rain or hills. It is used by human beings as well as animals and also for irrigation. The tank water is not pure. Hence, it should be boiled or sieved before using for drinking purposes. 

4. River Water: Rivers flow fast and their water remains in contact with air, hence at their source the water is pure but it becomes polluted due to the poisonous hilly vegetations and mixing of water from city drains. 

5. Well Water: Well water especially water from deep wells is pure. Its purity should be conserve

(a) Carbon monoxide

a)Carbon monoxide 

The answer is (c) Forests do not conserve soil

Forest prevent soil erosion, forest adds fertility to the soil by adding humus hence they help conserve the soil and its fertility

1. Clean toilets: Toilets should be kept neat and clean by getting them washed with disinfectants because dirty toilets become the cause of many infectious diseases.

2. Water Disposal System should be proper and adequate because: 

1. It will remove the human excreta easily. 

2. There will be no need for manual labour. 

3. It is an easy and cheap method. 

4. Mosquitoes and flies do not breed over the human excreta. 

5. There are minimum chances of spread of diseases.

3. Removal or Disposal of the School Refuse: 

School refuse should be collected in containers from where it should be shifted to the municipal vans which are emptied in the far off places (away from residential area) where it is buried in the ground. Thus:

1. The school remains clean and tidy. 

2. Untidy things are removed and thrown out. 

3. Diseases are avoided. 

4. Environment remains healthy.

5. Schools give beautiful and neat look. 

6. Flies and mosquitoes do not breed. 

7. Children grow and develop in healthy atmosphere.

The concept of School Environment is interpreted in terms of location of school i.e., its surroundings, direction, provision for light, air etc. playground and the health related facilities such as disposal of wastes, water outlets, cleanliness, water and electricity. The school having healthy and suitable environment promotes healthy physical and mental development of its children. Some of these factors are considered while selecting the location for starting the school and others are kept in view at the time of constructing the school building.