Some Basic Concepts of Chemistry

The mass of a mixture containing NaCl and NaBr is 4.0 g . If Na is $30 \%$ of the total mixture, the composition of NaCl in the mixture is $(\mathrm{Na}=23 \mathrm{u}, \mathrm{Cl}=35.5 \mathrm{u}, \mathrm{Br}=80 \mathrm{u})$

Two acids $A$ and $B$ are titrated separately, 25 mL of $0.5 \mathrm{M} \mathrm{Na}_2 \mathrm{CO}_3$ solution requires 10 mL of $A$ and 40 mL of $B$ for complete neutralisation. The volume (in L ) of $A$ and $B$ required to produce 1 L of 1...

The composition of a sample of wustite is $\mathrm{Fe}_{0.93} \mathrm{O}_{1.00}$. Percentage of iron in the form of $\mathrm{Fe}^{3+}$ ion is nearly

An ideal gas mixture of $\mathrm{C}_2 \mathrm{H}_6$ and $\mathrm{C}_2 \mathrm{H}_4$ occupies a volume of 28 L at 1 atm and 273 K . This mixture reacts completely with 128 g of $\mathrm{O}_2$ to produce $\mathrm{CO}_2$ and $\mathrm{H}_2 \mat...

Complete combustion of ethane gives only gaseous products. In a closed vessel, 15 g of ethane and 112 g of $\mathrm{O}_2$ were allowed to completely react. What is the total number of moles of gaseous substances present in the vessel at the...

1.84 g of a mixture of $\mathrm{CaCO}_3$ and $\mathrm{MgCO}_3$ is strongly heated to get a residue of 0.96 g . The percentage of $\mathrm{CaCO}_3$ in the mixture is

Consider the following
(A) 0.0025
(B) 500.0
(C) 2.0034
Number of significant figures in $A, B$ and $C$ respectively, are

209 g of an element reacts with chlorine to form 315.5 g of its chloride. What is the weight (in g ) of oxygen that reacts with 418 g of same element ?
\((\mathrm{Cl}=35.5 \mathrm{u} ; \mathrm{O}=16 \mathrm{u})\)

Observe the following
I. 0.0063
II. 132.00
III. 1004
The number of significant figures in I, II and III is respectively.

10 g of a metal $(M)$ reacts with oxygen to form 11.6 got oxide. What is the equivalent weight of $M$ ?

Identify the correct statements from the following.
I. Reaction of hydrogen with fluorine occurs even in dark.
II. Manufacture of ammonia by Haber process is an endothermic reaction.
III. HF is electron rich hydride.

100 mL of $\frac{M}{10} \mathrm{Ca}\left(\mathrm{NO}_3\right)_2$ and 200 mL of $\frac{M}{10} \mathrm{KNO}_3$ solutions are mixed. What is the normality of resulted solution with respect to $\mathrm{NO}_3^{-}$?

0.1 mole of potassium permanganate was heated at $300^{\circ} \mathrm{C}$. What is weight (ing) of the residue?

\((\mathrm{Mn}=55 \mathrm{u}, \mathrm{~K}=39 \mathrm{u}, \mathrm{O}=16 \mathrm{u})\)

A flask contains 98 mg of $\mathrm{H}_2 \mathrm{SO}_4$. If $3.01 \times 10^{20}$ molecules of $\mathrm{H}_2 \mathrm{SO}_4$ are removed from the flask. The number of moles of $\mathrm{H}_2 \mathrm{SO}_4$ remained in flask is
$$ \left(N_A=6.0...

The density of nitric acid solution is $1.5 \mathrm{~g} \mathrm{~mL}^{-1}$. Its weight percentage is 68 . What is the approximate concentration (in $\mathrm{mol} \mathrm{L}^{-1}$ ) of nitric acid ?
$$ (\mathrm{N}=14 \mathrm{u} ; \mathrm{O}=...

$\mathrm{Xe}(g)+2 \mathrm{~F}_2(g) \xrightarrow[7 \text { bar }]{873 \mathrm{~K}} \mathrm{XeF}_4(\mathrm{~s})$The ratio of $\mathrm{Xe}: \mathrm{F}_2$ required in the above reaction is

The mass % of urea solution is 6 . The total weight of the solution is 1000 g . What is its concentration in $\mathrm{mol} \mathrm{L}^{-1}$ ? (Density of water $=1.0 \mathrm{~g} \mathrm{~mL}^{-1}$ )( $\mathrm{C}=12 \mathrm{u}, \mathrm{N}=14...

At STP ' $x$ ' $g$ of a metal hydrogen carbonate $\left(M \mathrm{HCO}_3\right)$ (molar mass $84 \mathrm{~g} \mathrm{~mol}^{-1}$ ) on heating gives $\mathrm{CO}_2$, which can completely react with 0.2 moles of MOH (molar mass $40 \mathrm{~g...

A hydrocarbon containing C and H has $92.3 \% \mathrm{C}$ When 39 g of hydrocarbon was completely burnt in 0 $X$ moles of water and $Y$ moles of $\mathrm{CO}_2$ were formed $\mathrm{H}_2$ with Na metal, What is the weight (in g) of ounp ${ ...

The concentration of 1 L of $\mathrm{CaCO}_3$ solution is 1000 ppm . What is its concentration in mol $\mathrm{L}^{-1}$ ?\((\mathrm{Ca}=40 \mathrm{u}, \mathrm{O}=16 \mathrm{u}, \mathrm{C}=12 \mathrm{u})\)

20 mL of 0.1 M HCl is added to the 30 mL of 0.1 M NaOH . To this solution extra 50 mL of water was added. What is the molarity of the final solution formed?

50 g of a substance is dissolved in 1 kg of water at \(+90^{\circ} \mathrm{C}\). The temperature is reduced to \(+10^{\circ} \mathrm{C}\). The density is increased from 1.1 to \(1.15 \mathrm{~g} \mathrm{~cc}^{-1}\). What is the % change of ...

What are \(x\) and \(y\) in the following reaction?
\(x \mathrm{~Pb}_3 \mathrm{O}_4 \longrightarrow y \mathrm{PbO}+\mathrm{O}_2\)

The statement related to law of definite proportions is

The empirical formula of calgon is

An alloy of metals X and Y weighs 12 g and
contains atoms X and Y in the ratio of 2 : 5.
The percentage of metal X in the alloy is 20
by mass. If the atomic mass of X is 40 amu
what is the atomic mass of metal Y ?

The complete combustion of one mole of
benzene produces .......... grams of carbon
dioxide.

\(7.8 \mathrm{~g}\) of a compound having molecular formula \(\mathrm{C}_6 \mathrm{H}_6\), on reacting with \(\mathrm{CH}_3 \mathrm{COCl} / \mathrm{AlCl}_3\) gives \(8.4 \mathrm{~g}\) of a product which has molecular formula $$\mathrm{C}_8 \...

\(0.63 \mathrm{~g}\) of oxalic acid is dissolved in order to obtain \(250 \mathrm{~cm}^3\) of its solution. Find the normality of this solution. [oxalic acid \(\left.(\mathrm{COOH})_2 \cdot 2 \mathrm{H}_2 \mathrm{O}\right]\)

If the volume of \(15.9 \mathrm{~g}\) of carbon tetrachloride is \(10 \mathrm{~mL}\), calculate its density.

When 20 g of CaCO\(_3\) is treated with 20 g of HCl, the mass of CO\(_2\) formed would be

If 0.2 moles of sulphuric acid is poured into
250 mL of water, calculate the concentration
of the solution.