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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:

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 \(NO_{2}\) and \(N_{2} O_{4}\)  is 38.3. The mole of \(NO_{2}\) 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 ${\mathrm{Ti}}_{1.44}<mspace\; width="1em"></mspace>\mathrm{O}.$ 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

At standard temperature and pressure (STP), the volume of oxygen required to completely combust 30 ml of acetylene under similar conditions 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:

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