Explore topic-wise InterviewSolutions in Current Affairs.

1. Quantization of electric charge. Conservation of electric charge.

2. No. According to quantisation of charge, total charge is Q = ne when ‘n’ is an integer. Here

n = \(\frac{0.8\times10^{-19}}{1.6\times10^-19}\)

1. Quantization of electric charge. Conservation of electric charge.

2. No. According to quantisation of charge, total charge is Q = ne when ‘n’ is an integer. Here

n = \(\frac{0.8\times10^{-19}}{1.6\times10^{-19}}\) = 0.5 n is a fractional value.

1. Electric dipole.

2.  \(\tau\) = P × E

= PE (θ = 90°) = q2aE

= 3 × 10⁶ × 5 × 10³ × 3 × 10⁵ Nm(∴ 2a = 5 × 10^-3)

3. The dipole undergoes for both translation and rotational motion.

Z = 107 (Group no. 7)

Y = 108 (Group no. 8)

X = 109 (Group no. 9)

A and B belong to same group of periodic table because they have same number of valence electrons.

A. Formic acid

B. Copper glance

The element with Z = 107, will be placed in 7th group, element with Z = 108 in group 8th.

(i) The electrons in a molecule are present in the various molecular orbitals as the electrons of atoms are present in the various atomic orbitals. 

(ii) The atomic orbitals of comparable energies and proper symmetry combine to form molecular orbitals. 

(iii) In a molecular orbital an electron is influenced by two or more nuclei depending upon the number of atoms in the molecule. 

(iv) The number of molecular orbital formed is equal to the number of combining atomic orbitals. When two atomic orbitals combine, two molecular orbitals are formed. One is known as bonding molecular orbital while the other is called antibonding molecular orbital. 

(v)The bonding molecular orbital has lower energy and hence greater stability than the corresponding antibonding molecular orbital. 

(vi) The electron probability distribution around a group of nuclei in a molecule is given by a molecular orbital. 

(vii) The molecular orbitals like atomic orbitals are filled in accordance with the aufbau principle obeying the Pauli’s exclusion principle and the Hund’s rule. 

a) High compressibility is due to large empty space between the gas molecules. 

b) Due to absence of attractive forces between the molecules, they can easily separate from one another. 

Correct Answer is: B. Secondary alcohol 

Addition of LiAlH₄ to ketones to give secondary alcohols and H₂O gives also secondary alcohol.

An atomic orbital is monocentric while a molecular orbital is polycentric.

 B. Secondary alcohol

Correct Answer is: (A) Ethanamine

• The ammonia is act as a nucleophile which attack through their nitrogen atom are termed as nitrogen nucleophile. 

• When Chloroethane on reacting with the ammonia then it gives the Ethanamine as a product by losing the hydrochloric acid.

(n 1) d¹ ns² for n 4 becomes 3d¹ 4s² . It lies in the 4th period and in the 3rd group.

The roots for 1, 1 and 5 are un, un and pent respectively. So, the symbol and IUPAC name of element with atomic number 115 is Uup and ununpentium respectively. The roots for 1, 0 and 7 are un, nil and sept respectively So, the symbol and IUPAC name of element with atomic number 107 are Uns and unnilseptium respectively.

It is formed by the combination of two hydrogen atoms. Each hydrogen atom has one electron in 1s orbital. Therefore, in all, there are two electrons in hydrogen molecule which are present in σ1s molecular orbital. So electronic configuration of the hydrogen molecule is H₂ : (σ1s)² . The bond order of H₂ molecule can be calculated as given below:

Bond order = 1(Nb-Na)/ 2 =1 .This means that the two hydrogen atoms are bonded together by a single covalent bond

Correct Answer is: (B) Alkyl amines 

LiAlH₄ reduces amides to amines. Mechanism depends slightly on whether amide has an N-H or not. Sodium borohydride (NaBH₄) is a mild reducing agent. It is only capable of reducing aldehydes and ketones.

Correct Answer is: (A) CH₃NC 

C₂H₃N is the formula of Methylnitrile.

True

Properties such as density, boiling point, melting point are physical properties and they can be observed or measured directly.

False

Both physical and chemical changes occur during burning of a candle. There is a change in the state of wax from solid state to liquid state and from liquid state to vapour state. Change in state of the matter is a physical change.

Burning involves the process of combustion. The candle is basically a carbon containing material which combines with oxygen to give out carbon dioxide. This process is a chemical change.

It belongs to the 15th group (P). It has 3 unpaired electrons.

(i) The outermost configuration of the element

= 2s² 2p⁴ (as it has 6 electrons in the outermost shell)

\(\therefore\) Electronic configuration of the element = 1s² , 2s² 2p⁴

\(\therefore\) Atomic number = 2+ 2 + 4 = 8

Hence, the element is oxygen.

(ii) Element with Z = 107 has five, Z = 108 has six electrons while Z = 109 has seven 6d-eletrons. Hence, these elements differ in the number of electrons in the 6dsubshell.

(iii) Z = 86 Atomic number of next noble gas = 86 + 32 = 118 Its symbol is Uuo.

When two H atoms come closer the following forces operate between them: 

a. Attractive : 

i.nucleus of atom and its electron 

ii.nucleus of one atom and electron of other. 

b.repulsive : 

i.electrons of two atoms. 

ii.nucleus of two atoms. 

It has been found experimentally that magnitude of attractive forces is more than repulsive forces hence two atoms come closer to each other and the potential energy of the system decreases. A stage is reached when attractive forces balance repulsive forces and the system acquires minimum energy .At this stage two hydrogen atoms are said to be bonded together.

Respiration and decomposition processes are exothermic process because: 

(i). We all get energy from the food we eat. 

(ii). During digestion, food is broken down into simpler substances.

(iii). For example, Carbohydrates (rice, potatoes, bread) are broken down to form glucose.

(iv). This glucose combines with oxygen and provides energy to the whole body.

We get from the food we eat. During digestion complex molecules of food are broken into simpler molecule such as glucose. This glucose combines with oxygen in the cells of our body and provides energy. Therefore respiration is considered an exothermic reaction.

Respiration is considered as an exothermic reaction because heat is released along with the form.ation of products.

Respiration is an exothermic process because energy is produced during this process.

(c) carbon monoxide

When there is excess of carbon dioxide in the air, and lack of trees or plants for consuming it in photosynthesis process then it acts as pollutant. Carbon dioxide is being increased continuously in atmosphere due to deforestation, burning of fossil fuels, industrialization, use of petrol and diesel in automobiles.

As a pollutant now carbon dioxide contributes to greenhouse effect and global warming.

(a) air pollution

The harmful substances like sewage, toxic materials, silt etc., when gets mixed with water, causes water pollution. The pollutants which cause water pollution are the chemical waste from industries, sewage, silt, agricultural chemicals and garbage thrown into water.

Water gets polluted in the following ways:

1. Water can be contaminated by human waste or sewage. 

2. Industries such as oil refineries, paper factories, textile and sugar mills and chemical factories discharge harmful chemicals into rivers and streams. These chemicals include arsenic, lead and flourides. 

3. Some industries and power plants releases hot water into the rivers. Hot water can also be considered as a pollutant. 

4. The excessive use of pesticides and fertilizers in agriculture also causes water pollution.

Yes, excess fertilizers and pesticides are among the many common pollutants that can degrade water quality.

Fertilizers are made of nutrients, such as nitrogen and phosphorus. When it rains, these nutrients are carried into the nearest river or other water bodies. Too many nutrients in water can cause algae to grow, which uses up the oxygen in the water, this process is called Eutrophication. Low levels of oxygen in water can adversely affect aquatic wildlife and even lead to killing of fish and other aquatic organisms.

Most of the chemical contents used in fertilizers are so poisonous that they also affect human life and whole food chain cycle. Fertilisers containing ammonia can be harmful to aquatic life if large amounts are deposited to surface waters.

Causes of water pollution are as follows -

• Throwing large quantities of garbage, untreated sewage (containing food wastes, detergents, microorganisms), dead bodies and many other harmful things directly in water
• Throwing non-biodegradable polythene bags, Idols of god and goddesses in water.
• Discharging of toxic chemical waste into river by industries. Increased level of chemicals in water bodies act as nutrients for algae and results in decrease in oxygen level which may kill aquatic organisms
• People bathing, washing clothes and defecating in the river.
• Releasing hot water from power plants and industries adversely affects or leads to death of plants and animals living in it
• Discharge of pesticides and insecticides from soil to river after rain.
• Water in sea gets polluted due to oil spills from ships and tankers while travelling.

Arsenic, lead, mercury and fluorides are the toxic metals whose compounds are present in industrial wastes.

When wood is burnt in a limited supply of oxygen, volatile materials present in it get removed and cooled to get wood tar and wood gas. 

The black residue left behind aftqr the reaction is known as charcoal. Advantages of using charcoal as a fuel over wood are: 

Burning of charcoal does not produce smoke. On the other hand, wood produces a lot of smoke on burning. For a given quantity, charcoal produces ,more heat than wood.

Ethene is formed when ethanol is heated with conc. H₂S0₄ at 170^o C. This reaction is called dehydration.

Difference in physical properties:

(a) Liquid at room temperature 

(b) Soluble in H₂O in all proportions

(a) 95.5 %

Rectified spirit is a mixture of 95.5 % of ethanol and 4.5 % of water

Methylated Spirit or Denatured Alcohol

Alcoholic drinks are heavily taxed by the government, so as to discourage people from over consuming it. Alcohol used for industrial and surgical purposes is not taxed heavily. But in order to prevent people from buying and consuming this alcohol, it is mandatory that ethyl alcohol be mixed with a certain percentage of highly poisonous methyl alcohol or methanol. This renders the ethyl alcohol unfit for human consumption. This mixture is called "Methylated Spirit". If chemicals like copper sulphate or pyridine are added to ethyl alcohol it is called 'denatured alcohol'.

Drinking alcohol and driving may cause serious accidents. To discourage this, police randomly test drivers for alcohol using a breath analyser. The breath analyser works because Alcohol makes the breath hotter which changes the machine reading.

(d) All of above

(c) ethanol and methanol (5%)

The compound which gives a brisk effervescence with sodium metal and not with sodium hydrogen carbonate is ethanol.