Explore topic-wise InterviewSolutions in .

Correct option is C) a = b

B) It has two elements

Correct option  (B) P is atom bomb and Q is hydrogen bomb.

Explanation:

P is biggest having a mass number 235 and showing nuclear fission reaction so it is an atom bomb, and Q is smaller having a mass number 2 and showing nuclear fusion reaction so it is a hydrogen bomb.

Correct option: (A) 0.5

Since, 1 mole of BaCO₃ contains 3 moles of oxygen

1.5 moles of oxygen ≡ \(\cfrac{1}{3}\) x 1.5 = \(\cfrac{1}{2}\) = 0.5

moles of BaCO₃

Correct option: (C) 2 g of H₂ 

Total number of atoms in molecule

= n x N_A x Atomicity

Atomicity’s of NH₃, O₂, H₂ and He molecules are 4, 2, 2 and 1 respectively.

17 g of NH₃ = 4 x N_A atoms

∴ 4.25 g of NH₃ = \(\left(\cfrac{4.25}{17}\right)\) x 4 x N_A = N_A atoms

32 g of O₂ = 2 x N_A atoms

∴ 8 g of O₂ = \(\cfrac{2\, \times \, 8}{32}\) x N_A = \(\cfrac{N_A}{2}\) atoms

2 g of H₂ = 2 x N_A atoms

= 2N_A atoms

4 g of He = N_A atoms

Thus, the system that contains 2 g of H₂ has maximum numbers of atoms.

Correct option is a. Both Na₂CO₃ and NaHCO₃ are completely neutralized

Correct  option: (C) 1.344 x 10¹⁸ 

22.4 L of water contains N_A molecules

22400 mL of water contains N_A molecules

1 mL of water i.e., 20 drops contains

\(\cfrac{N_A}{22400} \) molecules

∴ 1 drop contains \(\cfrac{N_A}{22400\, \times 20} \) = \(\cfrac{6.022\, \times\, 10^{23}}{448\, \times 10^3} \)

= 1.344 x 10¹⁸

A) A and R are true, A is supported by R

Correct option is A) MgCl₂

The weights of the flask and its contents do not change before and after reaction.

Yes, the contents in the flask are changed as lead iodide and potassium nitrate.

The hydrogen bomb consists of heavy isotopes of hydrogen (deuterium and tritium) alongwith lithium-6. The explosion of hydrogen bomb is done by using an atom bomb. When the aton bomb is exploded, its fission reaction produces a lot of heat which raises the temperature of deuterium and tritium to 107^oC in a few microseconds. Then fusion reactions of deuterium and tritium take place producing a tremendous amount of energy. This explodes the hydrogen bomb. Lithium-6 is used to produce more tritium needed for fusion.

Correct option: (C) kg C^-1 

Correct option: (D) Distilled water

Correct option (A) The control rods are fully inserted into the graphite   

Explanation:

 The control rods absorb all the neutrons, stopping the nuclear chain reaction.

Magnesium on burning in air gives a bright light and ash is remained. The ash is magnesium oxide.

(a) Control rods control the rate of fission by absorbing the excess neutrons and preventing the fission reaction from going out of control. 

(b) Heat is removed from the nuclear reactor core with the help of liquid sodium, which absorbs the heat and transfers it to the heat exhanger. This heat is used for converting water in the heat exchanger into steam, which is then used to produce electricity by rotating a turbine and its shaft connected to a generator.

1. No, we cannot get the same result. 

2. When the conical flask is not closed, some gases will leave out the flask during chemical reaction.

Uranium-235.

Correct option: (D) silicon

(i) 92 grams of sodium:

Given: Mass of sodium = 92g

Molar mass = 23g/mol

To calculate the number of moles, we apply the formula:

Number of moles =\(\frac{Mass\,of\,sodium}{Molar\,mass\,of\,sodium}\)

Number of moles = \(\frac{92g}{23 g/mol}\)

⇒ Number of moles = 4 mol

Thus, the number of moles in 92 grams of sodium is 4 mol.

(ii) 108 grams of aluminium:

Given: Mass of aluminium = 108g

Molar mass = 27g/mol

To calculate the number of moles, we apply the formula:

Number of moles = \(\frac{Mass\,of\,aluminium}{Molar\,mass\,of\,aluminium}\)

Number of moles = \(\frac{108g}{27 g/mol}\)

⇒ Number of moles = 4 mol

Thus, the number of moles in 108 grams of aluminium is 4 mol.

 It is given that nitrogen and oxygen are combined together in the ratio of 7:16 by mass. 

Mass of nitrogen = 14u 

Mass of oxygen = 16u and mass of O2 = 16× 2 = 32u 

Hence, we can write 14:32 which is equal to 7:16 

Therefore, the formula of the oxide is NO₂ and its name is nitrous dioxide.

1. Yes, but we cannot observe the conservation of mass. 

2. When the experiment is conducted in a closed container where there is no scope for oxygen to escape, we can observe the conservation of mass. But in this condition this experiment is not possible.

Nuclear energy is generated by the process of nuclear fusion or nuclear fission.

Nuclear fission is a process in which nucleus of heavy elements like uranium divides into two smaller nuclei when bombarded with some neutron. During fission of uranium, 200MeV energy is released.

(a) Uranium-235 

(b) No 

(c) Nuclear fission 

(d) Moderator slows down the speed of neutrons to make them fit for causing fission. 

(e) Boron rods are used to absorb excess neutrons and prevent the fission reaction from going out of control. 

(f) Liquid sodium or carbon dioxide gas is used as a ‘coolant’ to transfer the heat produced to heat exchanger for converting water into steam.

(A) (i), (ii) and (iii) 

The fission of an atom of uranium produced  10 million times the energy produced by the combustion of an atom of carbon from coal.

Radiation therapy

Correct option: (C) photovoltaic

Correct option is (c) MCI₃

Proportion of oxygen = 7.4 : 10 

Proportion of mercury = 92.6 : 125 

\(\Rightarrow \,\frac{7.4}{10}=\frac{92.6}{125}\Rightarrow0.74=0.74\)

∴ They follow law of constant proportions.

Uranium 238 or U-238

Correct option: (C) Inorganic

Correct option is (b) 9

1. Burning fossil fuels cause air pollution 

2. Assembly of a device with solar cells causes environmental damage.

Correct option is (b) 3

Correct option is (b) 35.0

Elements cannot be broken down into simpler substances while compounds can be broken down into simpler substances by chemical changes.

A good fuel would be one which is:- 

Easily accessible 

Easy to store and transport 

Economical 

And would do a large amount of work per unit volume or mass

A molecule is an assembly of atoms having a fixed composition, structure and distinctive, measurable properties.

Data Analytics

1. Knowledge of chemistry is required in the studies of physics, biological sciences, applied sciences, and earth and space sciences.

2. Chemistry is involved in every aspect of day-to-day life, i.e. the air we breathe, the food we eat, the fluids we drink, our clothing, transportation and fuel supplies, etc.

Hence, 

Chemistry is called a central science.

Technological development in sophisticated instruments have expanded knowledge of chemistry which, now, has been used in applied sciences such as medicine, dentistry, engineering, agriculture and in daily home use products. 

Hence,

Due to development and advancement in science and technology, chemistry has developed as modem science.

Chemical substances that cannot be broken down into similar one are known as elements.

Burning fossil fuels (coal and petroleum) cause air pollution. 

The oxides of carbon, nitrogen and sulphur that are released on burning fossil fuels, they are acidic oxides. This lead to acid rain which affects air and water resources. 

Increased emissions of Carbon dioxide gas contribute to greenhouse effect.

Cloud Computing

(C) Cloud Computing

(Normal temperature and pressure or standard temperature and pressure). The temp 273 K (0 °C) and pressure 101.3 Kpa (or N/m²) or l atm = 760 mm of Hg level are taken as STP or NTP.