31 Year NEET Previous Year Questions: States of Matter - 2 (Old NCERT) - NEET MCQ

Charle’s Law - The volume of the given mass of a gas increases or decreases by of its volume at 0°C for each degree rise or fall of temperature at constant pressure.

at constt. Pressure

According to kinetic gas equatiion

 u = root mean square velocity

Absolute zero is the temperature at which kinetic energy of gas molecules becomes zero i.e. all molecular motion ceases.

Vander Waal's equation for 1 mole :

Here,  represent the intermolecularforces. (V – b) is the corrected volume.

At low pressure and high temperature: At low pressure volume correction for 1 mole of a gas in negligible, i.e b = 0 thus the gas equation becomes

At higher pressure, the pressure correction for 1 mole of gas in negligible i.e 

or (P + 0) (V – b) = RT
or P (V_m – b) = RT
or PV_m = RT + Pb

Here volume is constant. Again the mass of H₂ is fixed so the number of moles of the gas do not change. As temperature increases the pressure also increases. The rate of collision among the gas molecules and their energy also increases.

According to Boyle’s law at constant temperature,  = constant

i.e higher will be the molar mass lower will be the value of urms.
Molecular masses of H₂, N₂, O₂ and HBr are 2, 28, 32 and 81. Hence the correct order is HBr < O₂ < N₂ < H₂

Velocity and hence the K.E is  maximum in the gaseous state.

Molecules in an ideal gas move with different speeds.

R = 0.082 litre atm K^–1 mole^–1 .

In the ideal gas, the intermolecular forces of attraction are negligible and hence it cannot be liquefied.

In the equation PV = nRT, n moles of the gas have volume V.

Average kinetic energy depends only on temperature

Hence 1 = 1 × 0.082 × T is 

per unit vol.

Most probable velocity 

Mean velocity 

Root mean square velocity 

At low temperature and high pressure.

u₂ = 2u₁

By definition of Nernst distribution law.
When a solute is shaken with two immiscible liquids, having solubility in both, the solute distributes itself between the two liquids in such a way that the ratio of its concentrations in two liquids is constant at a given temperature, provided the molecular state of the solute remains the same in both the liquids.

A substance exists as a liquid above its m. pt. and below its b. pt.

Given initial volume (V₁) = 500 ml ; Initial temperature (T₁) = 27ºC = 300 K and final temperature (T₂) = –5ºC = 268 K.
From Charle’s law :

Where V₂ = New volume of gas

Given initial volume (V₁) = 600 c.c.;
Initial pressure (P₁) = 750 mm and final volume (V₂) = 500 c.c. according to Boyle’s law,

P₁V₁ = P₂V₂
 or 750 × 600 = P₂ × 500

Therefore increase in pressure = (900 – 750)              

= 150 mm.

By Ideal gas equation P₁V =  n₁RT  

At low pressure and high temperature real gas nearly behave like ideal gas. Hence deviation is minimum from ideal behaviour.

Rate of diffusion depend upon molecular weight

r₁ = r₂ if M₁ = M₂

Hence compounds are N₂O and CO₂ as both have same molar  mass i.e 22

Applying Boyle's law P₁V₁ = P₂V₂ for both gase