SAT (Stage-2) Mock Test - 48

The velocity of sound in gas is proportional to the square root of adiabatic elasticity.
The formula is,

Both the spheres will expand almost equally. This is because both the sphere are of the same material.

K₂SO₄ does not undergo hydrolysis.

Potassium sulphate is salt of strong acid and strong base. Such salts do not undergo hydrolysis when dissolved in water and their solutions are neutral. In this case, neither the cations nor the anions undergo hydrolysis.

NaCl has the highest melting and boiling points amongst all as it is an ionic compound which has strong electrostatic bonds between two oppositely charged ions. It leads to a compact packing. Therefore, it becomes very difficult for the compound to change its molecular structure to change its state and a lot of heat energy is required to do so. Hence, its melting and boiling points are very high.

Molecular weight of H₂SO₄ = 98 g
Therefore, 4.25 g of H₂SO₄ is equivalent to 4.25/98 = 0.043 moles of H₂SO₄ molecules.
Therefore, 4.25 g of H₂SO₄ contains 0.043 × 6.022 × 10²³ molecules.
= 0.261 × 10²³ molecules or 2.61 × 10²² molecules

Statement I is correct as kinetic energy of molecules increases during the processes of evaporation and boiling. The molecules can overcome interparticle forces of attraction and escape into the vapour phase.
Statement II is also correct. At a reduced external pressure, the interparticle forces of attraction decrease and molecules require lesser kinetic energy to overcome these forces. Hence, the boiling point decreases and evaporation also occurs at a lower temperature.
However, statement III is incorrect as only the rate of evaporation is affected by the surface area.

Alloys are an example of solid in solid solution and are homogenous in nature. These are chemically more stable than their constituent metals; therefore alloys are designed for specific resistance to actions like corrosion, fatigue, wear, and temperature. Hence, option (2) is incorrect.

Valency, oxidation state and atomic number are always written as integers. But, atomic weight can be in decimals.

Statement I is correct as the last electron in p-block elements enters p-subshell of the outermost shell. Since, p-subshell can accommodate 6 electrons, p-block has six groups.
Statement II is incorrect because the outermost shell in lanthanoids is the sixth shell.
Statement III is correct. While writing the electronic configuration, the outer most electron in lanthanoids enters fourth shell.
Statement IV is incorrect because the periodic table has 7 periods and 18 groups.

M, a newly discovered element, is placed in group IA of the periodic table because it forms an ionic chloride having the formula MCl.

Pyridine is a heterocyclic compound as it is a cycle that does not only contain carbon atoms, but also nitrogen. The structure of pyridine is as follows.

Control rods are used in nuclear reactors to control the fission rate of uranium and plutonium. They are composed of chemical elements such as boron, silver, indium and cadmium and are capable of absorbing many neutrons without themselves fissioning.

Aluminium is trivalent and magnesium is bivalent, hence magnesium is more reactive.

The element with lower valency is more reactive.

All burning processes involve a chemical change.

Burning of both coal and graphite is a chemical change and may be represented as follows.

Hence, statement (3) is wrong.