Some basic concepts of chemistry practice · Hard

A mixture contains 1 mole each of $\mathrm{Fe}^{+2}$ and $\mathrm{Fe}^{+3}$ ions volume of $1 \mathrm{~M} \mathrm{~KMnO}_4$ required by mxiture in the oxidation of the given mixture is

Assume that the atomic mass of oxygen is $7.$ A sample of $11 \mathrm{~g}$ of an oxide of uranium contains $10 \mathrm{~g}$ of uranium. Which of the following formula for the oxide is compatible with the data?

In the mixture of $\left(\mathrm{NaHCO}_3+\mathrm{Na}_2 \mathrm{CO}_3\right)$, volume of $\mathrm{HCl}$ required is $x \mathrm{~mL}$ with phenolphthalein indicator and $y \mathrm{~mL}$, with methyl orange indicator in the same titration. Hence, volume of $\mathrm{HCl}$ for complete reaction of $\mathrm{Na}_2 \mathrm{CO}_3$ is:

If mass percentage of sulphur in a biomolecule 0.02% then the number of sulphur atoms present in 16 g of biomolecule is

Mole fraction of the solute in a $1.00$ molal aqueous solution is

3L mixture of ${O}_2(\mathrm{g})$ and ${N}_2(\mathrm{g})$ is passed through ozonizer. The gas mixture obtained contains ${O}_2, {O}_3$ and ${N}_2$ gases only. This obtained mixture is passed through alkaline pyrogallol and then through turpentine oil, there were $1100 \mathrm{~mL}$ and $600 \mathrm{~mL}$ volume contractions respectively. The volume of ${O}_2(\mathrm{g})$ and ${N}_2(\mathrm{g})$ in the original mixture respectively is

A quantity of $2.3 \mathrm{~g}$ of a mixture of $\mathrm{NO}_2$ and $\mathrm{N}_2 \mathrm{O}_4$ has a pressure of $0.82 \mathrm{~atm}$, at temperature $\text{T K}$ in a container of volume $\text{V}$ litres such that the ratio, $\text{T : V}$ is $300: 1$ in magnitude. What is the degree of dissociation of $\mathrm{N}_2 \mathrm{O}_4?$

A 10 mg effervescent tablet containing sodium bicarbonate and oxalic acid releases 0.25 mL of $C{O_2}$ at T = 298.15 K and $p = 1$ bar. If molar volume of $C{O_2}$ is 25.0 L under such condition, what is the percentage of sodium bicarbonate in each tablet?
[Molar mass of $NaHC{O_3} = \,84\,\,g\,\,mo{l^{ - 1}}]$

A volume of $500 \mathrm{~ml}$ of a $0.1 \mathrm{~M}$ solution of ${AgNO}_3$ is added to $500 \mathrm{~ml}$ of $0.1 \mathrm{~M}$ solution of ${KCl}.$ The concentration of nitrate ion in the resulting solution is

Common salt obtained from sea-water contains $8.775 \% \mathrm{NaCl}$ by mass. The number of formula units of $\mathrm{NaCl}$ present in $25 \mathrm{~g}$ of this salt is :

Hydrazine ${N}_2 {H}_4$ (used as a fuel in rocket system) can be produced according to the following reaction.

${ClNH}_2+2 {NH}_3 \rightarrow {N}_2 {H}_4+{NH}_4 {Cl}$

When $1.0 \mathrm{~kg} \, {ClNH}_2$ is reacted with excess of ${NH}_3,$ $473 \mathrm{~g}$ of ${N}_2 {H}_4$ is produced. What is the percentage yield?

A mixture contains $\mathrm{FeSO}_4$ and $\mathrm{Fe}_2\left(\mathrm{SO}_4\right)_3.$ If both $\mathrm{FeSO}_4$ and $\mathrm{Fe}_2\left(\mathrm{SO}_4\right)_3$ provide equal number of sulphate ions then, the ratio of $\mathrm{Fe}^{2+}$ and $\mathrm{Fe}^{3+}$ ions in mixture is

If air contains ${\mathrm{N}_2}$ and ${\mathrm{O}_2}$ in volume ratio $4:1$. The average vapour density of air is:

The ratio of masses of oxygen and nitrogen of a particular gaseous mixture is 1 : 4. The ratio of number of their molecule is

21.75g of $Mn{O_2}$ on reaction with HCl forms 2.8 L of $C{l_2}\left( g \right)$ at STP, the percentage purity of $Mn{O_2}$ is (atomic mass of Mn = 55u)
$Mn{O_2} + 4HCl \to MnC{l_2} + C{l_2} + 2{H_2}O$

A gaseous alkane is exploded with oxygen.
The volume of $\text{O}_2$ for complete combustion to
the volume of $\text{CO}_2$ formed is in $7:4$ ratio. The
molecular formula of alkane is

Boron has two isotopes boron-10 and boron-11 whose percentage abundances are $19.6 \%$ and $80.4 \%$ respectively. What is the average atomic mass of boron?