NEET ChemistryUpdated 19 Oct 2026

Gasesous State*: NEET PYQs and weightage

Gasesous State* carries 2.1 of 100 Chemistry marks in NEET by past-paper share: 15 of the 707 tagged NEET Chemistry PYQs in the ViJEEta bank (NEET 2013–2026). It ranks 24 of 26 Chemistry chapters.

Take the 25-question Gasesous State* test Formula sheet ↓All NEET Chemistry chapters

2.1/100 Weight in Chemistry

Exam importance (2/5, by past-paper share)

15 NEET PYQs

330 Practice questions

70 With measured difficulty

How the weight is computed: this chapter's tagged NEET PYQs divided by all tagged NEET Chemistry PYQs in the bank (15 of 707), times 100, with repeated questions counted once. The bank does not store the year of each NEET question, so none is printed. Computed from the bank at build time. Updated 19 Oct 2026.

Gasesous State*: formula sheet for NEET

14 formulas, each with when to use it. Copy it onto one page of your notebook: that page is this chapter's handbook.

Ideal (perfect) gas equation
$p V = n R T$
Use it when: any three of $p$ , $V$ , $n$ , $T$ are known and you need the fourth (real gases obey it exactly only as $p \to 0$ )
Kelvin from Celsius
$T / K = θ /^{\circ} C + 273.15$
Use it when: a temperature is given in $^{\circ} C$ , since every gas formula needs $T$ in kelvin
Amount of gas
$n = \frac{mass}{M} (M = molar mass in g mol^{- 1})$
Use it when: the question gives grams or mass percentages instead of moles
Mole fraction
$x_{J} = \frac{n _{J}}{n}$
$n = n_{A} + n_{B} + \dots$
Use it when: you need each gas's share of a mixture
Sum of mole fractions
$x_{A} + x_{B} + \dots = 1$
Use it when: you need the last mole fraction after finding all the others
Dalton's law of partial pressures
$p = p_{A} + p_{B} + \dots$
Use it when: gases that do not react share one container and you need the total pressure
Partial pressure
$p_{J} = x_{J} p$
Use it when: you know the total pressure and the mixture's composition
Molar mass from molecular mass
$M = m N_{A}$
Use it when: switching between the mass of one molecule ( $m$ ) and the mass of a mole ( $M$ )
Number density of molecules
$\frac{N}{V} = \frac{n N _{A}}{V}$
Use it when: you need how many molecules sit in each unit of volume
Pressure from kinetic theory
$p = \frac{n M ⟨ v ^{2} ⟩}{3 V}$
$p V = \frac{1}{3} n M ⟨ v^{2} ⟩$
Use it when: you need to link gas pressure to molecular speeds
One direction carries a third
$⟨ v_{x}^{2} ⟩ = ⟨ v_{y}^{2} ⟩ = ⟨ v_{z}^{2} ⟩ = \frac{1}{3} ⟨ v^{2} ⟩$
Use it when: you go from one-direction motion to the full speed in the pressure result
Speed from its components
$v^{2} = v_{x}^{2} + v_{y}^{2} + v_{z}^{2}$
Use it when: you combine velocity components into a speed
Momentum change in one wall collision
$m v_{x} \to - m v_{x}$
$Δ p_{x} = 2 m v_{x} (the y and z parts stay the same)$
Use it when: you derive the force or pressure that molecules exert on a wall
Wall hits in time Δt
$number = \frac{1}{2} (\frac{n N _{A}}{V}) A v_{x} Δ t$
Use it when: you count the molecules that reach a wall of area $A$ (the $\frac{1}{2}$ is there because only half of them move towards it)

Trap

finding a partial pressure straight from the mass percentage. First convert each mass to moles (n = mass/M), then find x_J, and only then use p_J = x_J p. Also put T in kelvin, never in °C.

How does NEET ask Gasesous State*?

8 real previous-year questions from this chapter, as printed in the paper, each with its worked solution. Answer the first one here with no sign-in.

Q1ChemistryNEET UG PYQIdeal Gas Equation and Its Applications

Try right here · No sign-in

The correction factor ‘a’ to the ideal gas equation corresponds to

Answer key (D) & worked solution

Correct answer: Option D

In real gas equation,

(P + \frac{a n ^{2}}{V ^{2}}) (V - nb) = n R T

van der Waal’s constant, ‘a’ signifies intermolecular forces of attraction.

Q2ChemistryNEET UG PYQMeasurable Properties of Gases

What fraction of one edge centred octahedral void lies in one unit cell of fee?

\frac{1}{3}

\frac{1}{4}

\frac{1}{12}

\frac{1}{2}

Answer key (B) & worked solution

Correct answer: Option B

→ Edge centered octahedral void is shared between four unit cells → Per unit cell contribution is 1/4

Q3ChemistryNEET UG PYQDalton's Law of Partial Pressure

Which one is not correct mathematical equation for Dalton's Law of partial pressure? Here p = total pressure of gaseous mixture

Ap = p

_{1}

+ p

_{2}

+ p

_{3}

p = n_{1} \frac{RT}{V} + n_{2} \frac{RT}{V} + n_{3} \frac{RT}{V}

_{i}

χ_{i} p

, where p

_{i}

= partial pressure of i

^{t h}

gas;

χ_{i}

= mole fraction of i

^{t h}

gas in gaseous mixture

_{i}

χ_{i} p_{i}^{o}

, where

χ_{i}

= mole fraction of i

^{t h}

gas in gaseous mixture p

_{i}

^{o}

= pressure of i

^{t h}

gas in pure state

Answer key (D) & worked solution

Correct answer: Option D

_{i}

χ_{i} p_{i}^{o}

is not correct expression for Dalton’s law

Q4ChemistryNEET UG PYQIdeal Gas Laws

A compound is formed by two elements

A

and B. The elements

B

forms cubic close packed structure and atoms of

A

occupy

1/3

of tetrahedral voids. If the formula of the compound is

A_{x} B_{y}

, then the value of

x + y

is in option

Answer key (D) & worked solution

Correct answer: Option D

\frac{1}{3} THV

\Rightarrow Z_{A} = \frac{1}{3} \times 8 = \frac{8}{3} Z_{B} = 4

\Rightarrow= \frac{8}{3} : 4

\Rightarrow \frac{2}{3} : 1

B CCP Z

_{B}

= 4

2 : 3

simplest formula $\begin{array}{*{20}{c}} {{{\text{A}}_2}}&{{\text{}}{{\text{B}}_3}} \\ \downarrow & \downarrow \\ {\text{x}}&{\text{y}} \end{array}$

x + y = 5

Q5ChemistryNEET UG PYQIdeal Gas Equation and Its Applications

Equal masses of H

_{2}

, O

_{2}

and methane have been taken in a container of volume V at temperature 27

^{0}

C in identical conditions. The ratio of the volumes of gases H

_{2}

: O

_{2}

: methane would be:

A16 : 1 : 2

B8 : 1 : 2

C8 : 16 : 1

D16 : 8 : 1

Answer key (A) & worked solution

Correct answer: Option A

From Avagadro's Law volume ∝ moles nH

_{2}

: nO

_{2}

:nmethane

Moles :

\frac{w}{2} : \frac{w}{32} : \frac{w}{16}

⇒ Ratio of volume

= \frac{w H _{2}}{2} : \frac{w O _{2}}{32} : \frac{w C H _{4}}{16}

= 16 : 1 : 2

Q6ChemistryNEET UG PYQDalton's Law of Partial Pressure

A mixture of

N_{2}

and Ar gases in a cylinder 7 g of

N_{2}

and 8 g of Ar. If the total pressure of the mixture of the gases in the cylinder is 27 bar, the partial pressure of

N_{2}

is: [use atomic masses (in g

m o l^{- 1}

): N = 14, Ar = 40]

A15 bar

B18 bar

C9 bar

D12 bar

Answer key (A) & worked solution

Correct answer: Option A

According to Dalton’s law

P_{N_{2}} = χ_{N_{2}} P_{total}

P_{N_{2}} = \frac{( \frac{7}{28} )}{( \frac{8}{40} + \frac{7}{28} )} \times 27

P_{N_{2}} = (\frac{0.25}{0.2 + 0.25}) \times 27

P_{N_{2}} = 15

bar

Q7ChemistryNEET UG PYQIdeal Gas Equation and Its Applications

Given van der Waals constant for NH

_{3}

, H

_{2}

_{2}

and CO

_{2}

are respectively 4.17, 0.244, 1.36 and 3.59, which one of the following gases is most easily liquefied?

_{2}

_{2}

CNH

_{3}

DCO

_{2}

Answer key (C) & worked solution

Correct answer: Option C

van der waal constant ‘a’, signifies intermolecular forces of attraction. Higher is the value of ‘a’, easier will be the liquefaction of gas.

Q8ChemistryNEET UG PYQGraham's Law of Diffusion and Effusion

Equal moles of hydrogen and oxygen gases are placed in a container with a pin-hole through which both can escape. What fraction of the oxygen escapes in the time required for one-half of the hydrogen to escape?

\frac{1}{2}

\frac{1}{8}

\frac{1}{4}

\frac{3}{8}

Answer key (B) & worked solution

Correct answer: Option B

Equal moles are given so partial pressure is equal (let = x)

\frac{r _{O_{2}}}{r _{H_{2}}} = \frac{M _{H_{2}}}{M _{O_{2}}} = \frac{V _{O_{2}}}{t _{O_{2}}} \times \frac{t _{H_{2}}}{V _{H_{2}}} = \frac{n _{O_{2}}}{t _{O_{2}}} \times \frac{t _{H_{2}}}{n _{H_{2}}} \frac{\frac{n _{O_{2}}}{t}}{\frac{\frac{x}{2}}{t}} = \frac{2}{32} = \frac{1}{4} \frac{\frac{n _{O_{2}}}{t}}{\frac{\frac{x}{2}}{t}} = \frac{1}{4} \Rightarrow \frac{n _{O_{2}}}{x} = \frac{1}{8}

Fraction of oxygen escaped

\frac{1}{8}

Which topics in Gasesous State* carry the most questions?

All 7 topics, by tagged PYQs, then practice questions. Counted from the bank. Updated 19 Oct 2026.

Topic	PYQs	Practice questions
Ideal Gas Equation and Its Applications	7	68
Ideal Gas Laws	3	36
Dalton's Law of Partial Pressure	2	160
Graham's Law of Diffusion and Effusion	1	31
Introduction to Gaseous State	1	28
Measurable Properties of Gases	1	3
Miscellaneous Examples	0	4

Why does Gasesous State* show "–" until you answer 3 questions?

Unknown is not zero. Until you answer at least 3 graded questions in Gasesous State*, ViJEEta shows – instead of a zero or a 50% default. Book exercises can raise chapter mastery up to 0.60, adaptive practice up to 0.75, and only a timed chapter test or mock can certify 0.80 and above.

How ViJEEta scores you

What happens when you test Gasesous State*?

Every chapter test is 25 questions. It starts at moderate difficulty and adapts after each saved answer. If you open a solution before answering, that attempt earns no credit, so your mastery stays honest.

Start the Gasesous State* test

Chapters either side of Gasesous State* by weight

Practical Chemistry Weight 2.5/100 Haloalkanes and Haloarenes Weight 2.4/100 General Organic Chemistry (Revision) and Isomerism Weight 2.0/100 Carboxylic Acids and Derivatives Weight 1.1/100

Gasesous State*: NEET PYQs and weightage

Gasesous State*: formula sheet for NEET

Ideal (perfect) gas equation

Kelvin from Celsius

Amount of gas

Mole fraction

Sum of mole fractions

Dalton's law of partial pressures

Partial pressure

Molar mass from molecular mass

Number density of molecules

Pressure from kinetic theory

One direction carries a third

Speed from its components

Momentum change in one wall collision

Wall hits in time Δt

How does NEET ask Gasesous State*?

Which topics in Gasesous State* carry the most questions?

Why does Gasesous State* show "–" until you answer 3 questions?

What happens when you test Gasesous State*?

Chapters either side of Gasesous State* by weight