Suppose two elements X and Y combine to form two compounds ${\mathrm{XY}}_2$ and ${\mathrm{X}}_2{\mathrm{Y}}_3$when 0.05 mole of${\mathrm{XY}}_2$ weighs 5 g while 3.011$\times$10²³ molecules of ${\mathrm{X}}_2{\mathrm{Y}}_3$ weighs 85 g. The atomic masses of x and y are respectively:

1.  20, 30

2.  30, 40

3.  40, 30

4.  80, 60

1.44 gram of titanium (At. wt. =48) reacted with excess of ${\mathrm{O}}_2$ and produce x gram of non-stoichiometric compound ${\mathrm{Ti}}_{1.44} \mathrm{O}.$ The value of x is:

1.  2

2.  1.77

3.  1.44

4.  None of the above

The impure 6 g of $\mathrm{NaCl}$ is dissolved in water and then treated with excess of silver nitrate solution. The weight of precipitate of silver chloride is found to be 14 g. The % purity of $\mathrm{NaCl}$ solution would be:

1.  95%

2.  85%

3.  75%

4.  65%

60 mL of a mixture of nitrous oxide and nitric oxide was exploded with excess of hydrogen. If 38 mL of ${\mathrm{N}}_2$ was formed, calculate the volume of each gas in the mixture. All measurements are made at constant P and T.

1.20 ml +30 ml

2. 44 ml + 16 ml

3. 10 ml+40 ml

4 .25 ml +25 ml

The haemoglobin from the red blood corpuscles contains approximately 0.33%  iron
by mass. The molar mass of haemoglobin is 67,200. The number of iron atoms in each molecule of haemoglobin is :
(atomic mass of iron=56):

Which mixture is lighter than humid air?

1.  ${\mathrm{N}}_2+{\mathrm{O}}_2+{\mathrm{SO}}_2$

2.  ${\mathrm{N}}_2+{\mathrm{O}}_2+{\mathrm{CO}}_2$

3.  ${\mathrm{N}}_2+{\mathrm{O}}_2+{\mathrm{C}}_2{\mathrm{H}}_6$

4.  ${\mathrm{N}}_2+{\mathrm{O}}_2+\mathrm{He}$

The mass of one molecule of compound ${\mathrm{C}}_{60} {\mathrm{H}}_{122}$ is:

1.  $1.3\times {10}^{-20} \mathrm{g}$

2.  $5.01\times {10}^{-21} \mathrm{g}$

3.  $3.72\times {10}^{-23} \mathrm{g}$

4.  $1.4\times {10}^{-21} \mathrm{g}$

Calculate the % of free ${\mathrm{SO}}_3$ in oleum (a solution of ${\mathrm{SO}}_3$ in ${\mathrm{H}}_2{\mathrm{SO}}_4$) that is labelled 109% ${\mathrm{H}}_2{\mathrm{SO}}_4$.

1. 40

2. 30

3. 50

4. None

The average atomic mass of magnesium is 24.31 a.m.u. Magnesium consists of three isotopes: \(^{24}Mg\), \(^{25}Mg \), and \(^{26}Mg\). The mole percentage of \(^{24}Mg\) is 79%, and the remaining 21% is a mixture of \(^{25}Mg \) and \(^{26}Mg\).
Calculate the mole percentage of \(^{26}Mg\).

1.  10 %
2.  11 %
3.  15 %
4.  16 %

The conversion of oxygen to ozone occurs to the extent of 15% only. The mass of ozone that can be prepared from 67.2 L oxygen at 1 atm and 273 K will be:

1. 14.4 gm

2. 96 gm

3. 640 gm

4. 64 gm