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.  $6.023\times {10}^{23}$

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 1.657 g. What is the atomic weight of X?

1.  35.5

2.  28.1

3.  128

4.  19.0

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 $\mathrm{Sr}{\left(\mathrm{OH}\right)}_2$. 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

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.  ${\mathrm{P}}_2$

2.  ${\mathrm{P}}_4$

3.  ${\mathrm{P}}_6$

4.  ${\mathrm{P}}_8$

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

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

What is the molar mass of diacidic organic Lewis base (B), if 12 g of chloroplatinate salt $\left({\mathrm{BH}}_2{\mathrm{PtCl}}_6\right)$ on ignition produced 5 gm residue of Pt?

1.  52

2.  58

3.  88

4.  None of these

What volume of ${\mathrm{O}}_2\left(\mathrm{g}\right)$ measured at 1 atm and 273 K will be formed by action of 100 mL of 0.5 N KMnO₄ on hydrogen peroxide in an acid solution? The skeleton equation for the reaction is
${\mathrm{KMnO}}_4+{\mathrm{H}}_2{\mathrm{SO}}_4+{\mathrm{H}}_2{\mathrm{O}}_2$$\to K_{2}S{O}_4+MnS{O}_4+O_2+H_{2}O$

1.  0.12 litre

2.  0.028 litre

3.  0.56 litre

4.  1.12 litre

Cisplatin, an anticancer drug, has the molecular formula $\mathrm{Pt}{\left({\mathrm{NH}}_3\right)}_2 {\mathrm{Cl}}_2$. What is the mass (in gram) of one molecule? (Atomic weights : Pt=195, H=1.0, N=14, Cl=35.5)

1.  $4.98\times {10}^{-21}$

2.  $4.98\times {10}^{-22}$

3.  $6.55\times {10}^{-21}$

4.  $3.85\times {10}^{-22}$