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 |
80%
From NCERT
NEET - 2024
Hints

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 |
55%
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
Hints

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 $$\mathrm{K}_2 \mathrm{SO}_6 \cdot \mathrm{Al}_2\left(\mathrm{SO}_4\right)_3 \cdot12 \mathrm{H}_2 \mathrm{O}$$
Subtopic:  Empirical & Molecular Formula |
56%
From NCERT
NEET - 2024
Hints

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 |
83%
From NCERT
NEET - 2024
Hints

The amount of glucose required to prepare 250 mL of $$\frac{M}{20}$$ aqueous solution is:
(Molar mass of glucose: 180 g $$\mathrm{mol ^{-1}}$$)
1. 2.25 g
2. 4.5 g
3. 0.44 g
4. 1.125 g
Subtopic:  Concentration Based Problem |
84%
From NCERT
NEET - 2024
Hints

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 |
83%
From NCERT
NEET - 2024
Hints

Mass of glucose $$\left(\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6\right)$$ required to be dissolved to prepare one litre of its solution which is isotone with $$15~g~L^{-1}$$solution of urea $$\mathrm{(NH_2 CONH_2)}$$ is:

(Given : Molar mass in g $$\mathrm{mol}^{-1}$$ C:12, H:1, O: 16, N:14 )

1. 55 g
2. 15 g
3. 30 g
4. 45 g
Subtopic:  Concentration Based Problem |
69%
From NCERT
NEET - 2024
Hints

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
 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.