# The mass of  CO2 produced by heating 20 g of 20% pure limestone as per the given below equation is:   $$\left[\mathrm{CaCO}_3 \stackrel{1200 \mathrm{~K}}{\longrightarrow} \mathrm{CaO}+\mathrm{CO}_2\right]$$ 1. 1.32 g  2. 1.12 g  3. 1.76 g  4. 2.64 g

Subtopic:  Equation Based Problem |
72%
From NCERT
NEET - 2023
Hints

Select the correct statements from the following:
 A: Atoms of all elements are composed of two fundamental particles. B: The mass of the electron is $$9.10939 \times 10^{-31} \mathrm{~kg} \text {. }$$. C: All the isotopes of a given element show same chemical properties. D: Protons and electrons are collectively known as nucleons. E: Dalton's atomic theory regarded the atom as an ultimate particle of matter.
Choose the correct answer from the option given below:
 1 B, C and E only 2 A, B and C only 3 C, D and E only 4 A and E only
Subtopic:  Introduction |
72%
From NCERT
NEET - 2023
Hints

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):
 1 0.705 m 2 1.208 m 3 1.165 m 4 0.858 m
Subtopic:  Concentration Based Problem |
65%
From NCERT
NEET - 2023
Hints

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.  $$\frac{1}{12}$$
2.  $$0.08$$
3.  $$\frac{1}{16}$$
4.  $$\frac{1}{20}$$
Subtopic:  Moles, Atoms & Electrons |
From NCERT
NEET - 2022
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The mass of a 2.5 mL solution (the density of the solution is 2.15 g/mL) in the correct significant figures is:

1.  5375 × 10–3 g
2.  5.4 g
3.  5.38 g
4.  53.75 g
Subtopic:  Introduction |
71%
From NCERT
NEET - 2022
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Match List-I with List-II:

 List-I List-II (a) 4.48 litres of O2 at STP (i) 0.2 moles (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 |
From NCERT
NEET - 2022
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Calculate the mass of 95% pure CaCO3 that will be required to neutralize 50 mL of 0.5 M HCl solution according to the following reaction.
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + 2H2O(l)
[Calculate up to the second place of decimal point]
 1 9.50 g 2 1.25 g 3 1.32 g 4 3.65 g
Subtopic:  Equation Based Problem |
53%
From NCERT
NEET - 2022
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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 |
79%
From NCERT
NEET - 2024
Hints

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 |
77%
From NCERT
NEET - 2024
4.74 g of an inorganic compound contains 0.39g of K, 0.27 g 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 $$\mathrm{KAl}\left(\mathrm{SO}_4\right)_2 \cdot 12 \mathrm{H}_2 \mathrm{O}$$ 2 $$\mathrm{K}_2 \mathrm{Al}_2\left(\mathrm{SO}_4\right)_6 \cdot 12 \mathrm{H}_2 \mathrm{O}$$ 3 $$\mathrm{K}_2 \mathrm{SO}_4 \cdot \mathrm{Al}_2\left(\mathrm{SO}_4\right)_3 \cdot24 \mathrm{H}_2 \mathrm{O}$$ 4 $$\mathrm{K}_2 \mathrm{SO}_6 \cdot \mathrm{Al}_2\left(\mathrm{SO}_4\right)_3 \cdot12 \mathrm{H}_2 \mathrm{O}$$