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A sample of pure compound is found to have Na = 0.0887 mole, O = 0.132 mole, C = 2.65 × 10²² atoms.
The empirical formula of the compound is 
(1) Na₂CO₃
(2) Na₃O₂C₅
(3) ${\mathrm{Na}}_{0.0887}{0}_{0.132}{\mathrm{C}}_{2.65\times {10}^{22}}$
(4) NaCO

The hydrated salt, Na₂SO₄.nH₂O, undergoes a 55% loss in mass on heating and becomes anhydrous. The value of n will be:
1. 5
2. 3
3. 7
4. 10

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

2.0 g sample containing ${\mathrm{Na}}_2{\mathrm{CO}}_3$and ${\mathrm{NaHCO}}_3$ loses 0.248 g when heated to 300$°$C, the temperature at which ${\mathrm{NaHCO}}_3$ decomposes to ${\mathrm{Na}}_2{\mathrm{CO}}_3$, ${\mathrm{CO}}_2$ and ${\mathrm{H}}_2\mathrm{O}$. What is the % of ${\mathrm{Na}}_2{\mathrm{CO}}_3$ in mixture?
1.66.5
2.50.6
3.60.5
4.6.65

The vapour density of a mixture containing ${\mathrm{NO}}_2$ and ${\mathrm{N}}_2{\mathrm{O}}_4$  is 38.3. The mole of ${\mathrm{NO}}_2$ in a 100 g mixture is -
[Vapour density = (Molar mass / 2)]
1. 0.437
2. 0.347
3. 0.557
4. 0.663

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

A gaseous mixture of ${\mathrm{H}}_2$ and ${\mathrm{CO}}_2$ gas contains 66 mass % of ${\mathrm{CO}}_2$. The vapour density of the mixture is:
1.  6.1
2.  5.4
3.  2.7
4.  10.8

How many moles of lead (II) chloride will be formed from a reaction between 6.5g of PbO and 3.2g of HCl?
(1) 0.044                           
(2) 0.333
(3) 0.011                           
(4) 0.029

The volume of oxygen at STP required to completely burn 30 ml of acetylene at STP is
(1) 100 ml
(2) 75 ml
(3) 50 ml
(4) 25 ml

KClO₃ on heating decomposes to KCl and O₂. The volume of O₂ at STP liberated by 0.1 mole KClO₃ is
(1) 4.36 L
(2) 3.36 L
(3) 2.36 L
(4) None of these

When 100 mL of PH₃ is decomposed, it produces phosphorus and hydrogen. The change in volume is
1. 50  mL increase
2. 500 mL decrease
3. 900 mL decrease
4. none of these

In the Haber process, 30 L of dihydrogen and 30L of dinitrogen were taken for the reaction, which yielded only 50% of the expected product. What will be the composition of the gaseous mixture under the said conditions in the end?
1. 20L ammonia, 10L nitrogen, 30L hydrogen
2. 20L ammonia, 25L nitrogen, 15L hydrogen
3. 20L ammonia, 20L nitrogen, 20L hydrogen
4. 10L ammonia, 25L nitrogen, 15L hydrogen