The maximum number of atoms is present in which of the following -

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%
From NCERT
NEET - 2020
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An oxide of iron contains 69.9% iron and 30.1% oxygen by mass. What is its empirical formula?

1. FeO

2. Fe2O3

3. Fe3O4

4. Fe3O2

Subtopic:  Empirical & Molecular Formula |
 61%
From NCERT
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If the density of the solution is 3.12 g ml-1, then what will be the mass of the 1.5 ml solution in two significant figures?

1. \(4.4~\mathrm{g}\) 2. \(4680 \times 10^{3} ~\mathrm{g}\)
3. \(4.7~\mathrm{g}\) 4. \(46.80~\mathrm{g}\)
Subtopic:  Introduction |
 78%
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Match the following physical quantities with units.

Physical quantity Unit
A. Molarity (i).  mol kg–1 
B.  Molality (ii). mol L–1
C.  Pressure (iii).  Candella
D. Luminous intensity (iv). Pascal

Codes:

A B C D
1. (i) (iv) (ii) (iii)
2. (ii) (i) (iv) (iii)
3. (i) (iv) (iii) (ii)
4. (iv) (i) (iii) (ii)
Subtopic:  Introduction |
 94%
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The density of a 2 M aqueous solution of NaOH is 1.28 g/cm3. The molality of the solution is: 
[molecular mass of NaOH = 40 gmol-1]

1. 1.20 m 2. 1.56 m
3. 1.67 m 4. 1.32 m
Subtopic:  Concentration Based Problem |
 73%
From NCERT
NEET - 2019
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Percentage of C, H & N of a compound is given as follows:
C=40%, H=13.33%, N=46.67%
The empirical formula of the compound will be:

1. CH2N

2. C2H4N

3. CH4N

4. CH3N

Subtopic:  Empirical & Molecular Formula |
 77%
From NCERT
AIPMT - 1998
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The number of significant figures in the following numbers are:

(I) 161 cm
(II) 0.0161
(III) 1.61


1. 3, 3, 3
2. 3, 4, 3
3. 3, 2, 3
4. 3, 4, 4

Subtopic:  Introduction |
 74%
From NCERT
AIPMT - 1998
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The mass of CaCO3 required to react completely with 25 mL of 0.75 M HCl according to the given reaction would be:

\(CaCO_3 (s)\ + \ HCl (aq)\ \rightarrow CaCl_2(aq)\ + CO_2(g)\ \\~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+ H_2O(l)\)

 

1. 0.36 g

2. 0.09 g

3. 0.96 g

4. 0.66 g

Subtopic:  Concentration Based Problem | Equation Based Problem |
 63%
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One mole of oxygen gas at STP is equal to:

(a) 6 .022× 1023 molecules of oxygen
(b) 6.022 × 1023 atoms of oxygen
(c) 16 g of oxygen molecule
(d) 32 g of oxygen

Choose the correct answer from the option given below: 

1. (a) and (b)
2. (a) and (c)
3. (a) and (d)
4. (c) and (d)
Subtopic:  Moles, Atoms & Electrons |
 72%
From NCERT
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Sulphuric acid reacts with sodium hydroxide as follows

H2SO4+2NaOHNa2SO4+2H2O

When 1L of 0.1 M sulphuric acid solution is allowed to react with 1 L of 0.1 M sodium hydroxide solution, the amount of sodium sulphate formed and its molarity in the solution obtained are respectively-

1. 0.1 M, 7.10 g 2. 7.10 g, 0.025 M
3. 0.025 M, 3.55 g 4. 3.55 g, 0.25 M
Subtopic:  Concentration Based Problem |
 58%
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