Calculate number of electrons present in 9.5 g of ${\mathrm{PO}}_4^{3-}$:

1.  $6$

2.  $5 {\mathrm{N}}_{\mathrm{A}}$

3.  $0.1 {\mathrm{N}}_{\mathrm{A}}$

4.  $4.7 {\mathrm{N}}_{\mathrm{A}}$

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

1.  $3 {\mathrm{N}}_{\mathrm{A}}$

2.  $30 {\mathrm{N}}_{\mathrm{A}}$

3.  $24 {\mathrm{N}}_{\mathrm{A}}$

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 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

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

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) ${\mathrm{P}}_4+5{\mathrm{O}}_2 \stackrel{}{\to } {\mathrm{P}}_4{\mathrm{O}}_{10}$
(2) ${\mathrm{P}}_4{\mathrm{O}}_{10}+6{\mathrm{H}}_2\mathrm{O} \stackrel{}{\to } 4{\mathrm{H}}_3{\mathrm{PO}}_4$

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