If Avogadro number NA, is changed from 6.022 x 1023 mol-1 to 6.022 x 1020 mol-1 this would change

(1) the definition of mass in units of grams

(2) the mass of one mole of carbon

(3) the ratio of chemical species to each other in a balanced equation

(4) the ratio of elements to each other in a compound

Subtopic:  Moles, Atoms & Electrons |
 76%
From NCERT
NEET - 2015
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints

6.02 x 1020 molecules of urea are present in 100 mL of its solution. The concentration of the solution is

(a) 0.02 M

(b) 0.01 M

(c) 0.001 M

(d) 0.1 M

Subtopic:  Concentration Based Problem |
 82%
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints

A mixture of methane and ethene in the molar ratio of x : y has a mean molar mass of 20. What would be the mean molar mass. if the gases are mixed in the molar ratio of y : x?

(1) 22                               

(2) 24

(3) 20.8                           

(4) 19

Subtopic:  Moles, Atoms & Electrons |
 60%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints

advertisementadvertisement

The volume of a drop of water is 0.0018 mL then the number of water molecules present in two drop of water at room temperature is:

1.  12.046×1019

2.  1.084×1018

3.  4.84×1017

4.  6.023×1023

Subtopic:  Moles, Atoms & Electrons |
 51%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints

Carbon and oxygen combine to form two oxides, carbon monoxide and carbon dioxide in which the ratio of the weights of carbon and oxygen is respectively 12 : 16 and 12 : 32. These figures illustrate the:

1.  Law of multiple proportions

2.  Law of reciprocal proportions

3.  Law of conservation of mass

4.  Law of constant proportions

Subtopic:  Introduction |
 76%
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 formula of an acid is HXO2. The mass of 0.0242 moles of the acid 1.657 g. What is the atomic weight of X?

1.  35.5

2.  28.1

3.  128

4.  19.0

Subtopic:  Moles, Atoms & Electrons |
 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

advertisementadvertisement

A 6.85 g sample of the hydrates SrOH2.xH2O is dried in an oven to give 3.13 g of anhydrous SrOH2. What is the value of x?   (Atomic weights : Sr=87.60, O=16.0, H=1.0)

1.  8

2.  12

3.  10

4.  6

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

A sample of phosphorus that weights 12.4 g exerts a pressure 8 atm in a 0.821 litre closed vessel at 527°C. The molecular formula of the phosphorus vapour is:

1.  P2

2.  P4

3.  P6

4.  P8

Subtopic:  Ideal Gas Law |
 81%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints

Phosphoric acid H3PO4 prepared in a two step process.

(1) P4+5O2  P4O10
(2) P4O10+6H2O  4H3PO4

We allow 62g of phosphorus to react with react with excess oxygen which form P4O10 in 85% yield. In the step (2) reaction 90% yield of H3PO4 is obtained. Produced mass of H3PO4 is:

1.  37.485 g

2.  149.949 g

3.  125.47 g

4.  564.48 g

Subtopic:  Equation Based Problem |
 66%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints

advertisementadvertisement

What volume of HCl solution of density 1.2 g/cm3 and containing 36.5% by weight HCl, must be allowed to react with zinc(Zn) in order to liberate 4.0 g of hydrogen?

1.  333.33 mL

2.  500 mL

3.  614.66 mL

4.  None of these

Subtopic:  Equation Based Problem |
 60%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints