৪৯তম বিসিএস ⎯ প্রাণ রসায়ন [৬০১]

Correct Answer: c) Boyle's Law. 
​Boyle's Law describes the inverse relationship between pressure and volume.
(P ∝ 1/V) at constant temperature.

Correct Answer: b) Low pressure and high temperature. 
​At low pressure, the particles are far apart, so their volume is negligible compared to the container volume. At high temperature, the particles move quickly, so intermolecular forces are negligible. These are the conditions where a real gas behaves most ideally.

Correct Answer: a) Strong intermolecular attractive forces. 
​
​A negative deviation means that the real gas pressure is lower than the pressure predicted by the ideal gas law. This occurs because attractive forces between gas particles pull them toward each other, reducing the force and frequency of their collisions with the container walls.

P_total = P_gas + P_water
⇒ 760 torr = P_gas + 23.8 torr
⇒ P_gas = 760 - 23.8 = 736.2 torr

A represent Iron(Fe). Then Iron salt used in anemia, Fe has d orbital and Fe⁺³ form blood red solution with NH₄CNS.

B represent Zn element thus, B can not be a transition element. ZnO is amphoteric and follow Aufbau principle 

Al⁺³ = 1S² 2S² 2P⁴
F^- = 1S² 2S² 2P⁴

1S Orbital is the smallest and every option have 2 election, thus 1S has maximum electron density. 

The de Broglie equation, λ = h/mθ, relates the wave-like behavior of particles to their momentum. It states that all matter exhibits wave-like properties, with the wavelength (λ) inversely proportional to the momentum (p) of the particle. The equation is derived from Einstein's mass-energy equivalence and the energy of a photon. 

SiO² show catenation property and form giant molecule. This is why it has higher melting point.

Nitrogen can not extend it's octate to accommodate 5 bond hence it can not form NCl₅

Since the nuclear charge increases in the order Na < Mg < Al, the pull on the 10 electrons becomes stronger, making the ionic radius smaller.

​Therefore, the correct order of ionic size is
Na⁺ > Mg²⁺ > Al³⁺

​Third ionisation energy is the highest.
​so option d) E₁ < E₂ < E₃ is correct.

F (Fluorine) and O (Oxygen) are nonmetals located in the upper right of the periodic table.
They have a strong desire to gain electrons to complete their octet, so they have very high (negative) electron affinities. Fluorine, being a halogen, has one of the highest electron affinities.
​
Si (Silicon) is a metalloid, located to the left of fluorine and oxygen. It has a moderate electron affinity.

​Ca (Calcium) is an alkaline earth metal in Group 2. Atoms in this group have a filled s subshell (ns²). Adding an electron to calcium would require placing it in a higher-energy p orbital, which is energetically unfavorable. Consequently, alkaline earth metals tend to have very low (often positive or slightly negative) electron affinities, meaning they resist gaining an electron.

PV = nRT is the equation for ideal Gas.

44g CO₂ is one mole. 
​If we insert n = 1 in the ideal gas equation then we find option (a)

Ideal gas have compressibility factor=1.

Bangladesh have 96% of CH₄ in it's Natural Gas.

In a constant temperature, change of pressure doesn't change the product of PV, thus constant.

Partial pressure of Oxygen Gas: {6/(6+14)} × 200 = 60mm

In Charles Law, Pressure remains constant

This is Lusaac's Law and the straight line at constant volume known as isochor