When \(1 \text{ dm}^3\) of \(\text{CO}_2\) gas is passed over hot coke, the volume of gaseous mixture after complete reaction at STP becomes \(1.4 \text{ dm}^3\). The composition of the gaseous mixture at STP is :
1. \(0.6 \text{ dm}^3\) of \(\text{CO},\) \(0.8 \text{ dm}^3\) of \(\text{CO}_2\)
2. \(0.8 \text{ dm}^3\) of \(\text{CO},\) \(0.8 \text{ dm}^3\) of \(\text{CO}_2\)
3. \(0.8 \text{ dm}^3\) of \(\text{CO},\) \(0.6 \text{ dm}^3\) of \(\text{CO}_2\)
4. \(0.6 \text{ dm}^3\) of \(\text{CO},\) \(0.4 \text{ dm}^3\) of \(\text{CO}_2\)
Subtopic:  Moles, Atoms & Electrons | Concentration Based Problem |
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Level 3: 35%-60%
NEET - 2026
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The number of hydrogen atoms present in 5.4 g of urea is :
(Given : Molar mass of urea : 60 g mol-1, NA : 6.022 × 1023 particles mol-1)
1. 2.168 × 1023
2. 2.168 × 1022
3. 1.084 × 1022
4. 1.084 × 1023
Subtopic:  Moles, Atoms & Electrons |
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Level 3: 35%-60%
NEET - 2026
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Consider the following data of compounds:
A. \(212 ~g ~\text{of}~Na_2CO_3 (s) \text{[molar mass}=106 ~g]\)
B. \(~248 g ~\text{of}~ {Na}_2 \mathrm{O}({s}) [\text{molar mass} =62 \mathrm{~g} ]\)
C. \(240 g ~\text{of} ~NaOH (s)~ [\text{molar mass} =40 \mathrm{~g} \)
D. \( 12 g~ \text{of}~ \mathrm{H}_2(\mathrm{~g})[ \text{molar mass} =2 \mathrm{~g}].\)
E. \( 220 g~ \text{of} ~\mathrm{CO}_2(\mathrm{~g})[\text{ molar mass }=44 \mathrm{~g}]\)
Which of the following represents a correct set of compounds having an equal number of atoms?
1. B, C, and D only 2. B, D, and E only
3. A, B, and C only 4. A, B, and D only
Subtopic:  Moles, Atoms & Electrons |
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Level 3: 35%-60%
NEET - 2025
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Which of the following contains the highest number of helium atoms?

1. 4 u of helium
2. 4 g of helium
3. 2.27 L of helium at STP
4. 4 mol of helium
Subtopic:  Moles, Atoms & Electrons |
 76%
Level 2: 60%+
NEET - 2024
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1.0 g of \(H_2\) has same number of molecules as in:
1. 14 g of \(N_2\) 2. 18 g of \(H_2O\)
3. 16 g of CO  4. 28 g of \(N_2\)
Subtopic:  Moles, Atoms & Electrons |
 80%
Level 1: 80%+
NEET - 2024
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Match List-I with List-II:

List-I
(Quantities)
List-II
(Corresponding Values)
(a) 4.48 litres of O2 at STP (i) 0.2 mole
(b) 12.022 × 1022 molecules of H2O (ii) 12.044 × 1023
molecules
(c) 96 g of O2 (iii) 6.4 g
(d) 88 g of CO2 (iv) 67.2 litres at STP
(Given - Molar volume of a gas at STP - 22.4 L)
Choose the correct answer from the options given below:
(a) (b) (c) (d)
1. (i) (iii) (iv) (ii)
2. (iii) (i) (iv) (ii)
3. (iv) (i) (ii) (iii)
4. (iii) (i) (ii) (iv)
Subtopic:  Moles, Atoms & Electrons |
Level 3: 35%-60%
NEET - 2022
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What fraction of Fe exists as Fe(III) in Fe0.96O?
(Consider Fe0.96 to be made up of Fe(II) and Fe(III) only)
1.  \(\dfrac{1}{12}\)
2.  \(0.08\)
3.  \(\dfrac{1}{16}\)
4.  \(\dfrac{1}{20}\)
Subtopic:  Moles, Atoms & Electrons |
Level 3: 35%-60%
NEET - 2022
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Which of the following contains the maximum number of atoms ?

1. 1 g of Mg(s) 2. 1 g of O2 (g)
3. 1 g of Li(s) 4. 1 g of Ag(s)
Subtopic:  Moles, Atoms & Electrons |
 79%
Level 2: 60%+
NEET - 2020
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One mole of carbon atoms has a mass of 12 g. Determine the number of atoms present in this sample:
(Given: Mass of \(C^{12}\) is 1.9926×10-23 g)

1. 1.2×1023 2. 6.022×1022
3. 12×1022 4. 6.022×1023
Subtopic:  Moles, Atoms & Electrons |
 81%
Level 1: 80%+
NEET - 2020
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The maximum number of water molecules among the following is:

1. 18 mL of water 
2. 0.18 g of water 
3. 0.00224 L water vapours at 1 atm and 273 K
4. 10-3 mol of water 

Subtopic:  Moles, Atoms & Electrons |
 59%
Level 3: 35%-60%
NEET - 2018
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