The percentage by volume of $C_3{H}_8$ in a gaseous mixture of $C_3{H}_8$, $C{H}_4$ and CO is 20. When 100 mL of the mixture is burnt in excess of $O_2$, the volume of $C{O}_2$ produced is:

1. 90 mL

2. 160 mL

3. 140 mL

4. None of the above

Find the percentage of oxygen present in the compound CaCO₃ and Ca₃(PO₄)₂.

1.  23.3%

2.  45.36%

3.  41.94%

4.  17.08%

A gaseous compound is composed of 85.7% by mass carbon and 14.3% by mass hydrogen. It's density is 2.28 g/litre at 300 K and 1.0 atm pressure. Determine the molecular formula of the compound:

1.  ${\mathrm{C}}_2{\mathrm{H}}_2$

2.  ${\mathrm{C}}_2{\mathrm{H}}_4$

3.  ${\mathrm{C}}_4{\mathrm{H}}_8$

4.  ${\mathrm{C}}_4{\mathrm{H}}_{10}$

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

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

100 mL of 10% NaOH (w/V) is added to 100 mL of 10% HCl (w/V). The resultant solution becomes:

1. Alkaline

2. Strongly alkaline

3. Acidic

4. Neutral

Find the mass of non-stoichiometric oxide Ti₁.₄₄O formed when 1.44 g of titanium reacts completely with excess O₂.
Given: atomic mass of Ti = 48 g mol⁻¹.

1. 2.00

2. 1.77

3. 1.44

4. None of the above

2Fe(NO₃)₃ + 3Na₂CO₃ → Fe₂(CO₃)₃ + 6NaNO₃

A 6.0 g impure sample of sodium chloride is dissolved in water and reacted with excess silver nitrate solution.
If 14.0 g of silver chloride is formed, determine the percentage purity of NaCl in the sample.

1. 95%

2. 85%

3. 75%

4. 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