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

 

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

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

2.0 g sample contain mixture of ${\mathrm{SiO}}_2$ and ${\mathrm{Fe}}_2{\mathrm{O}}_3$, on very strong heating leave a residue weighing 1.96 g. The reaction responsible for loss of weight is ${\mathrm{Fe}}_2{\mathrm{O}}_3 \left(\mathrm{s}\right) \stackrel{}{\to } {\mathrm{Fe}}_3{\mathrm{O}}_4 \left(\mathrm{s}\right) + {\mathrm{O}}_2 \left(\mathrm{g}\right)$ (unbalance equation)

What is the percentage by mass of ${\mathrm{SiO}}_2$ in original sample?

1.  10%

2.  20%

3.  40%

4.  60%

For the reaction; 
\(2Fe{(NO_3)}_3 + 3Na_2CO_3 \rightarrow Fe_2{(CO3)}_3 + 6NaNO_3\)
Initially if 2.5 mole of \(Fe{(NO_3)}_3 \) and 3.6 mole of \(Na_2CO_3\) is taken. If 6.3 mole of \(NaNO_3\) is obtained then % yield of given reaction is:

1.  50

2.  84

3.  87.5

4.  100

0.8 mole of a mixture of CO and CO₂ requires exactly 40 gram of NaOH in a solution for complete conversion of all the CO₂ into Na₂CO₃. How many moles more of NaOH would it require for conversion into Na₂CO₃, if mixture (0.8 mole) is completely oxidised to CO₂?

1.  0.2

2.  0.6

3.  1

4.  1.5

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%

25.4 g of ${\mathrm{I}}_2$ and 14.2 g  of ${\mathrm{Cl}}_2$ are made to react completely to yield a mixture of ICI and ICI₃. The mole of ICI and ICI₃ formed, is respectively -

1. 0.5, 0.2

2. 0.1, 0.1

3. 0.1, 0.3

4. 0.3, 0.4

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

Copper forms two oxides. For the same amount of copper, twice as much oxygen was used to form first oxide than to form second one. What is the ratio of the valencies of copper in first and second oxides?

1. 2:5

2. 1:6

3. 2:1

4. 1:2