Among the following, choose the ones with equal number of atoms
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. \( 220 g~ \text{of} ~\mathrm{CO}_2(\mathrm{~g})[\text{ molar mass }=44 \mathrm{~g}]\)
Choose the correct answer from the options given below:
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 |
 53%
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NEET - 2025
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Dalton's Atomic theory could not explain which of the following? 
1. Law of multiple proportion
2. Law of gaseous volume
3. Law of conservation of mass 
4. Law of constant proportion 
Subtopic:  Introduction |
 61%
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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 |
 77%
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NEET - 2024
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1 gram of sodium hydroxide was treated with 25 mL of 0.75 M HCl solution, the mass of sodium hydroxide left unreacted is equal to :

1. 250 mg
2. Zero mg
3. 200 mg
4. 750 mg
Subtopic:  Millimole/Equivalent Concept |
 54%
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NEET - 2024
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A compound X contains 32% of A, 20% of B and remaining percentage of C. Then, the empirical formula of X is :
(Given atomic mass of A = 64; B = 40; C = 32u)
1. ABC3
2. AB2C2
3. ABC4
4. A2BC2
Subtopic:  Empirical & Molecular Formula |
 76%
From NCERT
NEET - 2024
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4.74 g of an inorganic compound contains 0.39g of K, 0.27 g of Al, 1.92 g of \(\mathrm{SO_4}\) radicals and 2.16 g of water. If molar mass of the compound is \(948 \mathrm{~g} \mathrm{~mol}^{-1},\) the molecular formula of the inorganic compound is:
1. \(\mathrm{{KAl}({SO}_4)_2 \cdot 12 {H}_2 {O}}\)
2. \(\mathrm{{K}_2 {Al}_2({SO}_4)_6 \cdot 12 {H}_2 {O}}\)
3. \(\mathrm{{K}_2 {SO}_4 \cdot {Al}_2({SO}_4)_3 \cdot24 {H}_2 {O}}\)
4. \(\mathrm{{K}_2 {SO}_6 \cdot {Al}_2({SO}_4)_3 \cdot12 {H}_2 {O}}\)
Subtopic:  Empirical & Molecular Formula |
 59%
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NEET - 2024
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Molar mass of a compound \(\text{(X)}\) whose \(2.6 \mathrm{~mol}\) weighs \(312 \mathrm{~g}\) is:
1. \(312 \mathrm{~g} \mathrm{~mol}^{-1}\) 2. \(120 \mathrm{~g} \mathrm{~mol}^{-1}\)
3. \(60 \mathrm{~g} \mathrm{~mol}^{-1}\) 4. \(811.2 \mathrm{~g} \mathrm{~mol}^{-1}\)
Subtopic:  Empirical & Molecular Formula |
 85%
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NEET - 2024
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How much glucose is needed to prepare 250 mL of a 1/20 M (M/20) glucose solution?
(Molar mass of glucose: 180 g/mol)

1. 2.25 g
2. 4.5 g
3. 0.44 g
4. 1.125 g
Subtopic:  Concentration Based Problem |
 81%
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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 |
 81%
From NCERT
NEET - 2024
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The mass of CO2 produced by heating 20 g of 20% pure limestone as per the equation given below is:
\(\mathrm{CaCO}_3(\mathrm{~s}) \xrightarrow{\text { heat }} \mathrm{CaO}(s)+\mathrm{CO}_2(\mathrm{~g})\)
1. 1.32 g  2. 1.12 g 
3. 1.76 g  4. 2.64 g
Subtopic:  Equation Based Problem |
 75%
From NCERT
NEET - 2023
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