Which of the following contains the greatest number of nitrogen atoms ?

1. 500 ml of 2.0 $\mathrm{M}<mspace\; width="1em"></mspace>{\mathrm{NH}}_3$

2. One mole of ${\mathrm{NH}}_4\mathrm{Cl}$

3. $6.02<mspace\; width="1em"></mspace>\times <mspace\; width="1em"></mspace>{10}^{23}$ molecules of ${\mathrm{NO}}_2$ gas

4. 22.4 litres of ${\mathrm{N}}_2$ gas at 0ºC and 1 atm.

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

The number of electrons present in 9.5 g of \(PO^{3-}_4\) are:
1. \(6\)
2. \(5~ N_A\)
3. \(0.1~ N_A\)
4. \(4.7 ~ N_A\)

The total no. of neutrons present in 54 mL ${\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$ are:

1.  $3<mspace\; width="1em"></mspace>{\mathrm{N}}_{\mathrm{A}}$

2.  $30<mspace\; width="1em"></mspace>{\mathrm{N}}_{\mathrm{A}}$

3.  $24<mspace\; width="1em"></mspace>{\mathrm{N}}_{\mathrm{A}}$

4.  none of these

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.  $12.046\times {10}^{19}$

2.  $1.084\times {10}^{18}$

3.  $4.84\times {10}^{17}$

4.  $6.023\times {10}^{23}$

Which of the following combinations illustrates the law of reciprocal proportions?
1. \(\mathrm{N}_2 \mathrm{O}_3, \mathrm{~N}_2 \mathrm{O}_4, \mathrm{~N}_2 \mathrm{O}_5 \)
2. \(\mathrm{NaCl}, \mathrm{NaBr}, \mathrm{Nal}\)
3. \(\mathrm{CS}_2, \mathrm{CO}_2, \mathrm{SO}_2 \)
4. \(\mathrm{PH}_3, \mathrm{P}_2 \mathrm{O}_3, \mathrm{P}_2 \mathrm{O}_5\)

Carbon and oxygen form two oxides, carbon monoxide and carbon dioxide, where the weight ratios of carbon to oxygen are 12:16 and 12:32, respectively. These ratios demonstrate:

1. Law of multiple proportions

2. Law of reciprocal proportions

3. Law of conservation of mass

4. Law of constant proportions

The formula of an acid is ${\mathrm{HXO}}_2.$ The mass of 0.0242 moles of the acid is 1.657 g.
The atomic weight of X is:

A 6.85 g sample of the hydrates $\mathrm{Sr}{\left(\mathrm{OH}\right)}_2.{\mathrm{xH}}_2\mathrm{O}$ is dried in an oven to give 3.13 g of anhydrous $\mathrm{Sr}{\left(\mathrm{OH}\right)}_2$. The value of x is - 

(Atomic weights : Sr=87.60, O=16.0, H=1.0)

1.  8

2.  12

3.  10

4.  6

The sulphate of the metal M contains 9.87% of M. This sulphate is isomorphous with ${\mathrm{ZnSO}}_4.7{\mathrm{H}}_2\mathrm{O}$. The atomic weight of M is:

1.  40.3

2.  36.3

3.  24.3

4.  11.3