Question 1: Palette 1/56

NEET 2026 MCQ

The number of hydrogen atoms present in 5.4 g of urea is:

(Given: Molar mass of urea : $60 \mathrm{~g} \mathrm{~mol}^{-1}$

$\mathrm{N}_{\mathrm{A}}: 6.022 \times 10^{23}$ particles $\mathrm{mol}^{-1}$ )

A

$1.084 \times 10^{23}$

B

$1.084 \times 10^{22}$

C

$2.168 \times 10^{22}$

D

$2.168 \times 10^{23}$

Question 2: Palette 2/56

NEET 2026 MCQ

When $1 \mathrm{dm}^3$ of CO₂ gas is passed over hot coke the volume of gaseous mixture after complete reaction at STP becomes $1.4 \mathrm{dm}^3$. The composition of the gaseous mixture at STP is :

A

$0.8 \mathrm{dm}^3$ of $\mathrm{CO}, 0.8 \mathrm{dm}^3$ of $\mathrm{CO}_2$

B

$0.8 \mathrm{dm}^3$ of $\mathrm{CO}, 0.6 \mathrm{dm}^3$ of $\mathrm{CO}_2$

C

$0.6 \mathrm{dm}^3$ of $\mathrm{CO}, 0.8 \mathrm{dm}^3$ of $\mathrm{CO}_2$

D

$0.6 \mathrm{dm}^3$ of $\mathrm{CO}, 0.4 \mathrm{dm}^3$ of $\mathrm{CO}_2$

Question 3: Palette 3/56

NEET 2026 MCQ

The numbers 17.0145 and 21.0235 were rounded to three figures after the decimal point. The resulting numbers, respectively, are

A

17.015 and 21.024

B

17.014 and 21.023

C

17.015 and 21.023

D

17.014 and 21.024

Question 4: Palette 4/56

NEET 2026 MCQ

The amount of carbon dioxide evolved upon complete combustion of $116 g$ of $n$-butane is

(Given: atomic mass in amu $\mathrm{H}=1, \mathrm{C}=12$ and $\mathrm{O}=16$ )

A

362 g

B

352 g

C

322 g

D

176 g

Question 5: Palette 5/56

NEET 2025 MCQ

Among the following, choose the ones with equal number of atoms.

A. 212 g of $\mathrm{Na}_2 \mathrm{CO}_3(\mathrm{~s})$ [molar mass $=106 \mathrm{~g}$ ]

B. 248 g of $\mathrm{Na}_2 \mathrm{O}(\mathrm{s})$ [molar mass $=62 \mathrm{~g}$ ]

C. 240 g of $\mathrm{NaOH}(\mathrm{s})$ [molar mass $=40 \mathrm{~g}$ ]

D. 12 g of $\mathrm{H}_2(\mathrm{~g})$ [molar mass $=2 \mathrm{~g}$ ]

E. 220 g of $\mathrm{CO}_2(\mathrm{~g})$ [molar mass $=44 \mathrm{~g}$ ]

Choose the correct answer from the options given below:

A

B, C, and D only

B

B, D, and E only

C

A, B, and C only

D

A, B, and D only

Question 6: Palette 6/56

NEET 2025 MCQ

Dalton's Atomic theory could not explain which of the following?

A

Law of multiple proportion

B

Law of gaseous volume

C

Law of conservation of mass

D

Law of constant proportion

Question 7: Palette 7/56

NEET 2024 MCQ

The amount of glucose required to prepare $250 \mathrm{~mL}$ of $\frac{\mathrm{M}}{20}$ aqueous solution is :

(Molar mass of glucose : $180 \mathrm{~g} \mathrm{~mol}^{-1}$)

A

2.25 g

B

4.5 g

C

0.44 g

D

1.125 g

Question 8: Palette 8/56

NEET 2024 MCQ

$1.0 \mathrm{~g}$ of $\mathrm{H}_2$ has same number of molecules as in:

A

$14 \mathrm{~g}$ of $\mathrm{N}_2$

B

$18 \mathrm{~g}$ of $\mathrm{H}_2 \mathrm{O}$

C

$16 \mathrm{~g}$ of $\mathrm{CO}$

D

$28 \mathrm{~g}$ of $\mathrm{N}_2$

Question 9: Palette 9/56

NEET 2024 MCQ

On complete combustion, 0.3 g of an organic compound gave 0.2 g of CO$_2$ and 0.1 g of H$_2$O. The percentage composition of carbon and hydrogen in the compound, respectively is:

A

4.07% and 15.02%

B

18.18% and 3.70%

C

15.02% and 4.07%

D

3.70% and 18.18%

Question 10: Palette 10/56

NEET 2024 MCQ

1 gram of sodium hydroxide was treated with $25 \mathrm{~mL}$ of $0.75 \mathrm{~M} \mathrm{~HCl}$ solution, the mass of sodium hydroxide left unreacted is equal to

A

750 mg

B

250 mg

C

Zero mg

D

200 mg

Question 11: Palette 11/56

NEET 2024 MCQ

The highest number of helium atoms is in

A

$4 \mathrm{~mol}$ of helium

B

$\mathrm{4 u}$ of helium

C

$4 \mathrm{~g}$ of helium

D

$2.271098 \mathrm{~L}$ of helium at STP

Question 12: Palette 12/56

NEET 2024 MCQ

A compound X contains $32 \%$ of A, $20 \%$ of B and remaining percentage of C. Then, the empirical formula of $\mathrm{X}$ is :

(Given atomic masses of A=64 ; B=40 ; C=32 u)

A

$\mathrm{A}_2 \mathrm{BC}_2$

B

$\mathrm{ABC}_3$

C

$\mathrm{AB}_2 \mathrm{C}_2$

D

$\mathrm{ABC}_4$

Question 13: Palette 13/56

NEET 2023 MCQ

The density of 1 M solution of a compound 'X' is 1.25 g mL$^{-1}$. The correct option for the molality of solution is (Molar mass of compound X = 85 g):

A

0.705 m

B

1.208 m

C

1.165 m

D

0.858 m

Question 14: Palette 14/56

NEET 2023 MCQ

The right option for the mass of $\mathrm{CO}_{2}$ produced by heating $20 \mathrm{~g}$ of $20 \%$ pure limestone is

(Atomic mass of $\mathrm{Ca}=40$ )

$\left[\mathrm{CaCO}_{3} \stackrel{1200 \mathrm{~K}}{\longrightarrow} \mathrm{CaO}+\mathrm{CO}_{2}\right]$

A

1.76 g

B

2.64 g

C

1.32 g

D

1.12 g

Question 15: Palette 15/56

NEET 2022 MCQ

The density of the solution is 2.15 g mL^$-$1, then mass of 2.5 mL solution in correct significant figures is :

A

53.75 g

B

5375 $\times$ 10^$-$3 g

C

5.4 g

D

5.38 g

Question 16: Palette 16/56

NEET 2022 MCQ

What fraction of Fe exists as Fe(III) in Fe_0.96O ?

(Consider Fe_0.96O to be made up of Fe(II) and Fe(III) only)

A

${1 \over {20}}$

B

${1 \over {12}}$

C

0.08

D

${1 \over {16}}$

Question 17: Palette 17/56

NEET 2022 MCQ

In one molal solution that contains 0.5 mole of a solute, there is

A

500 mL of solvent

B

500 g of solvent

C

100 mL of solvent

D

1000 g of solvent

Question 18: Palette 18/56

NEET 2022 MCQ

What mass of 95% pure CaCO₃ will be required to neutralise 50 mL of 0.5 M HCl solution according to the following reaction?

CaCO_3(s) + 2HCl_(aq) $\to$ CaCl_2(aq) + Co_2(g) + 2H₂O_(l)

[Calculate upto second place of decimal point]

A

1.25 g

B

1.32 g

C

3.65 g

D

9.50 g

Question 19: Palette 19/56

NEET 2021 MCQ

An organic compound contains 78% (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is : [Atomic wt. of C is 12, H is 1]

A

CH₄

B

CH

C

CH₂

D

CH₃

Question 20: Palette 20/56

NEET 2020 MCQ

Which one of the following has maximum number of atoms?

A

1 g of Mg(s) [Atomic mass of Mg = 24]

B

1 g of O₂(g) [Atomic mass of O = 24]

C

1 g of Li(s) [Atomic mass of Li = 7]

D

1 g of Ag(s) [Atomic mass of Ag = 108]

Question 21: Palette 21/56

NEET 2020 MCQ

The number of protons, neutrons and electrons in ¹⁷⁵₇₁Lu, respectively, are :

A

104, 71 and 71

B

71, 71 and 104

C

175, 104 and 71

D

71, 104 and 71

Question 22: Palette 22/56

NEET 2019 MCQ

The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber’s process is :

A

10

B

20

C

30

D

40

Question 23: Palette 23/56

NEET 2018 MCQ

A mixture of 2.3 g formic acid and 4.5 g oxalic acid is treated with conc. H₂SO₄ . The evolved gaseous mixture is passed through KOH pellets. Weight (in g) of the remaining product at STP will be

A

1.4

B

3.0

C

2.8

D

4.4

Question 24: Palette 24/56

NEET 2018 MCQ

In which case is number of molecules of water maximum?

A

18 mL of water

B

0.18 g of water

C

0.00224 L of water vapours at 1 atm and 273 K

D

10^–3 mol of water

Question 25: Palette 25/56

NEET 2017 MCQ

Which of the following is dependent on temperature?

A

Molarity

B

Mole fraction

C

Weight percentage

D

Molality

Question 26: Palette 26/56

NEET 2016 MCQ

Suppose the elements X and Y combine to form two compounds XY₂ and X₃Y₂. When 0.1 mole of XY₂ weights 10 g and 0.05 mole of X₃Y₂ weighs 9 g, the atomic weights of X and Y are

A

40, 30

B

60, 40

C

20, 30

D

30, 20

Question 27: Palette 27/56

NEET 2015 MCQ

The number of water molecules is maximum in

A

1.8 gram of water

B

18 gram of water

C

18 moles of water

D

18 molecules of water

Question 28: Palette 28/56

NEET 2015 MCQ

What is the mole fraction of the solute in a 1.00 m aqueous solution?

A

1.770

B

0.0354

C

0.0177

D

0.177

Question 29: Palette 29/56

NEET 2015 MCQ

What is the mass of the precipitate formed when 50 mL of 16.9% solution of AgNO₃ is mixed with 50 mL of 5.8% NaCl solution ? (Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5

A

3.5 g

B

7 g

C

14 g

D

28 g

Question 30: Palette 30/56

NEET 2015 MCQ

If Avogadro number N_A, is changed from 6.022 $ \times $ 10²³ mol^$-$1 to 6.022 $ \times $ 10²⁰ mol^$-$1, this would change

A

the mass of one mole of carbon

B

the ratio of chemical species to each other in a balanced equation

C

the ratio of elements to each other in a compound

D

the definition of mass in units of grams.

Question 31: Palette 31/56

NEET 2015 MCQ

A mixture of gases contains H₂ and O₂ gases in the ratio of 1 : 4 (w/w). What is the molar ratio of the two gases in the mixture ?

A

16 : 1

B

2 : 1

C

1 : 4

D

4 : 1

Question 32: Palette 32/56

NEET 2014 MCQ

1.0 g of magnesium is burnt with 0.56 g O₂ in a closed vessel, Which reactant is left in excess and how much ? (At. wt. Mg = 24, O = 16)

A

Mg. 0.16 g

B

O₂, 0.16 g

C

Mg, 0.44 g

D

O₂ , 0.28 g

Question 33: Palette 33/56

NEET 2014 MCQ

Equal masses of H₂, O₂ and methane have been taken in a container of volume V at temperature 27^oC in identical conditions. The ratio of the volumes of gases H₂ : O₂ : methane would be

A

8 : 16 : 1

B

16 : 8 : 1

C

16 : 1 : 2

D

8 : 1 : 2

Question 34: Palette 34/56

NEET 2014 MCQ

When 22.4 liters of H_2(g) is mixed with 11.2 litres of Cl_2(g), each at S.T.P. the moles of HCl_(g) formed is equal to

A

1 mol of HCl_(g)

B

2 mol of HCl_(g)

C

0.5 mol of HCl_(g)

D

1.5 mol of HCl_(g)

Question 35: Palette 35/56

NEET 2013 MCQ

In an experiment it showed that 10 mL of 0.05 M solution of chloride required 10 mL of 0.1 M solution of AgNO₃, which of the following will be the formula of the chloriode (X stands for the symbol of the element other than chlorine)

A

X₂Cl₂

B

XCl₂

C

XCl₄

D

X₂Cl

Question 36: Palette 36/56

NEET 2013 MCQ

6.02 $ \times $ 10²⁰ molecules of urea present in 100 mL of its solution. The concentration of solution is

A

0.001 M

B

0.1 M

C

0.02 M

D

0.01 M

Question 37: Palette 37/56

NEET 2013 MCQ

How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2.0 M HNO₃? The concentrated acid is 70% HNO₃.

A

70.0 g conc. HNO₃

B

54.0 g conc. HNO₃

C

45.0 g conc. HNO₃

D

90.0 g conc. HNO₃

Question 38: Palette 38/56

NEET 2011 MCQ

Which has the maximum number of molecules among the following ?

A

44 g CO₂

B

48 g O₃

C

8 g H₂

D

64 g SO₂

Question 39: Palette 39/56

NEET 2010 MCQ

25.3 g of sodium carbonate, Na₂CO₃ is dissolved in enough water to make 250 mL of solution. If sodium carbonate dissociates completely, molar concentration of sodium ion, Na⁺ and carbonate ions, CO${}_3^{2 - }$ are respectively (Molar mass of Na₂CO₃ = 106 g mol^$-$1)

A

0.955 M and 1.910 M

B

1.910 M and 0.955 M

C

1.90 M and 1.910 M

D

0.477 M and 0.477 M

Question 40: Palette 40/56

NEET 2010 MCQ

The number of atoms in 0.1 mol of a triatomic gas is (N_A = 6.02 $ \times $ 10²³ mol^$-$1)

A

6.026 $ \times $ 10²²

B

1.806 $ \times $ 10²³

C

3.600 $ \times $ 10²³

D

1.800 $ \times $ 10²²

Question 41: Palette 41/56

NEET 2009 MCQ

10 g of hydrogen and 64 g of oxygen were filled in a steel vessel and exploded. Amount of water produced in this reaction will be

A

3 mol

B

4 mol

C

1 mol

D

2 mol

Question 42: Palette 42/56

NEET 2008 MCQ

An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, 38.71% and H, 9.67%. The empirical formula of the compound would be

A

CHO

B

CH₄O

C

CH₃O

D

CH₂O

Question 43: Palette 43/56

NEET 2008 MCQ

How many moles of lead (II) chloride will be formed from a reaction between 6.5 g of PbO and 3.2 g HCl ?

A

0.011

B

0.029

C

0.044

D

0.333

Question 44: Palette 44/56

NEET 2008 MCQ

What volume of oxygen gas (O₂) measuread at 0^oC and 1 atm, is needed to burn completely 1 L of propane gas (C₃H₈) measured under the same conditions ?

A

5 L

B

10 L

C

7 L

D

6 L

Question 45: Palette 45/56

NEET 2007 MCQ

Concentrated aqueous sulphuric acid is 98% H₂SO₄ by mass and has a density of 1.80 g mL^$-$1. Volume of acid required to make one litre of 0.1 M H₂SO₄ solution is

A

16.65 mL

B

22.20 mL

C

5.55 mL

D

11.10 mL

Question 46: Palette 46/56

NEET 2007 MCQ

An element, X has the following isotopic composition:
²⁰⁰X : 90%  ¹⁹⁹X : 8.0%  ²⁰²X : 2.0%

The weighted average atomic mass of the naturally occuring element X is closest to

A

201 amu

B

202 amu

C

199 amu

D

200 amu

Question 47: Palette 47/56

NEET 2005 MCQ

The mole fraction of the solute in one molal aqueous solution is

A

0.009

B

0.018

C

0.027

D

0.036

Question 48: Palette 48/56

NEET 2004 MCQ

The maximum number of molecules is present in

A

15 L of H₂ gas at STP

B

5 L of N₂ gas at STP

C

0.5 g of H₂ gas

D

10 g of O₂ gas

Question 49: Palette 49/56

NEET 2002 MCQ

2.5 litre of 1 M NaOH solution is mixed with another 3 litre of 0.5 M NaOH solution. Then find out molarity of resultant solution.

A

0.80 M

B

1.0 M

C

0.73 M

D

0.50 M

Question 50: Palette 50/56

NEET 2002 MCQ

The percentage of C, H and N in an organic compound are 40%, 13.3% and 46.7% respectively then empirical formula is

A

C₃H₁₃N₃

B

CH₂N

C

CH₄N

D

CH₆N

Question 51: Palette 51/56

NEET 2002 MCQ

Which has maximum molecules?

A

7 g N₂

B

2 g H₂

C

16 g NO₂

D

16 g O₂

Question 52: Palette 52/56

NEET 2001 MCQ

Molarity of liquid HCl, if density of solution is 1.17 g/ce is

A

36.5

B

18.25

C

32.05

D

42.10

Question 53: Palette 53/56

NEET 2001 MCQ

Percentage of Se in peroxidase anhydrous enzyme is 0.5% by weight (at. wt. = 78.4) then minimum molecular weight of peroxide anhydrous enzyme is

A

1.568 $ \times $ 10⁴

B

1.568 $ \times $ 10³

C

15.68

D

2.136 $ \times $ 10⁴

Question 54: Palette 54/56

NEET 2001 MCQ

Specific volume of cylinfrical virus particle is 6.02 $ \times $ 10^$-$2 cc/g whose radius and length are 7 $\mathop A\limits^ \circ $ and 10 $\mathop A\limits^ \circ $ respectively. If _NA = 6.02 $ \times $ 10²³, find molecular weight of virus.

A

15.4 kg/mol

B

1.54 $ \times $ 10⁴ kg/mol

C

3.08 $ \times $ 10⁴ kg/mol

D

3.08 $ \times $ 10³ kg/mol

Question 55: Palette 55/56

NEET 2000 MCQ

Volume of CO₂ obtained by the complete decomposition of 9.85 g of BaCO₃ is

A

2.24 L

B

1.118 L

C

0.84 L

D

0.56 L

Question 56: Palette 56/56

NEET 2000 MCQ

Oxidation numbers of A, B, C are + 2, +5 and $-$2 respectively. Possible formula of compound is

A

A₂(BC₂)₂

B

A₃(BC₄)₂

C

A₂(BC₃)₂

D

A₃(B₂C)₂