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

Which of the following represents the atomic mass of element X in an acid with the molecular formula HXO₂, if 0.0242 mol of the acid has a mass of 1.657 g?

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 ${\mathrm{ZnSO}}_4.7{\mathrm{H}}_2\mathrm{O}$. What is the atomic weight of M?

1.  40.3

2.  36.3

3.  24.3

4.  11.3

Sulphur burns according to the reaction

 $\frac{1}{8}{\mathrm{S}}_8\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)$ $\stackrel{}{\to }$ ${\mathrm{SO}}_2\left(\mathrm{g}\right)$
What volume of air, at 1 atm and 273 K, containing 21%  oxygen by volume is required to completely burn sulphur $\left({\mathrm{S}}_8\right)$ present in 200 g of the sample?
(This sample contains 20% inert material which does not burn)

1.  23.52 litre

2.  320 litre

3.  112 litre

4.  533.33 litre

Phosphoric acid $\left({\mathrm{H}}_3{\mathrm{PO}}_4\right)$ prepared in a two step process.

(1) ${\mathrm{P}}_4+5{\mathrm{O}}_2<mspace\; width="1em"></mspace>\stackrel{}{\to }<mspace\; width="1em"></mspace>{\mathrm{P}}_4{\mathrm{O}}_{10}$
(2) ${\mathrm{P}}_4{\mathrm{O}}_{10}+6{\mathrm{H}}_2\mathrm{O}<mspace\; width="1em"></mspace>\stackrel{}{\to }<mspace\; width="1em"></mspace>4{\mathrm{H}}_3{\mathrm{PO}}_4$

We allow 62g of phosphorus to react with react with excess oxygen which form ${\mathrm{P}}_4{\mathrm{O}}_{10}$ in 85% yield. In the step (2) reaction 90% yield of ${\mathrm{H}}_3{\mathrm{PO}}_4$ is obtained. Produced mass of ${\mathrm{H}}_3{\mathrm{PO}}_4$ is:

1.  37.485 g

2.  149.949 g

3.  125.47 g

4.  564.48 g