# The empirical formula of an oxide of iron, which has 69.9% iron and 30.1% oxygen by mass is - 1. FeO 2. Fe2O3 3. Fe3O4 4. Fe3O2

Subtopic:  Empirical & Molecular Formula |
62%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

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 |
79%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

Match the following physical quantities with units.

 Physical quantity Unit A. Molarity 1. mol kg-1 B. Molality 2. mol L-1 C. Pressure 3. Candela D. Luminous intensity 4. Pascal

Codes

 A B C D 1. 1 4 2 3 2. 2 1 4 3 3. 1 4 3 2 4. 4 1 3 2
Subtopic:  Introduction |
94%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

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
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

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. $C{H}_{2}N$

2. ${C}_{2}{H}_{4}N$

3. $C{H}_{4}N$

4. $C{H}_{3}N$

Subtopic:  Empirical & Molecular Formula |
76%
From NCERT
AIPMT - 1998
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The number of significant figures in the following numbers is:

 (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 |
73%
From NCERT
AIPMT - 1998
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The mass of CaCO3 required to react completely with 25 mL of 0.75 M HCl according to the given reaction would be:

CaCO3(s) + HCl(aq) ➡ CaCl2(aq) + CO2(g) + H2O(l)

1. 0.36 g

2. 0.09 g

3. 0.96 g

4. 0.66 g

Subtopic:  Concentration Based Problem | Equation Based Problem |
62%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

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

1. (a) and (b)

2. (a) and (c)

3. (a) and (d)

4. (c) and (d)

Subtopic:  Moles, Atoms & Electrons |
74%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

Sulphuric acid reacts with sodium hydroxide as follows

${\mathrm{H}}_{2}{\mathrm{SO}}_{4}+2\mathrm{NaOH}\to {\mathrm{Na}}_{2}{\mathrm{SO}}_{4}+2{\mathrm{H}}_{2}\mathrm{O}$

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 |
54%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The correct match is:
 List I List II a. Micro i. ${10}^{-15}$ m b. Mega ii. ${10}^{-6}$ m c. Giga iii. ${10}^{6}$ m d. Femto iv. ${10}^{9}$ m

 a b c d 1. i iv iii ii 2. iii iv ii i 3. ii iii iv i 4. i iii iv ii
Subtopic:  Introduction |
87%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch