Some Basic Concepts Of Chemistry - PYQs

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

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

\(7.8 \mathrm{~g}\) 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 \(\mathrm{C}_8 \mathrm{H}_8 \mathrm{O}\). Calculate the percentage yield of the product \(\mathrm{C}_8 \mathrm{H}_8 \mathrm{O}\). (Given, atomic weights of \(\mathrm{H}, \mathrm{C}\) and \(\mathrm{O}\) respectively are 1, 12 and 16)

\(0.63 \mathrm{~g}\) 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.

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

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 empirical formula of calgon is

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

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 molarity of the solution?

The concentration of 1 L of $\mathrm{CaCO}_3$ solution is 1000 ppm . What is its concentration in mol $\mathrm{L}^{-1}$ ?

$$(\mathrm{Ca}=40 \mathrm{u}, \mathrm{O}=16 \mathrm{u}, \mathrm{C}=12 \mathrm{u})$$

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 $=1.0 \mathrm{~g} \mathrm{~mL}^{-1}$ )

( $\mathrm{C}=12 \mathrm{u}, \mathrm{N}=14 \mathrm{u}, \mathrm{O}=16 \mathrm{u}, \mathrm{H}=1 \mathrm{u}$ )

$\mathrm{Xe}(g)+2 \mathrm{~F}_2(g) \xrightarrow[7 \text { bar }]{873 \mathrm{~K}} \mathrm{XeF}_4(\mathrm{~s})$

The ratio of $\mathrm{Xe}: \mathrm{F}_2$ required in the above reaction is

The 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 ?

$$(\mathrm{N}=14 \mathrm{u} ; \mathrm{O}=16 \mathrm{u} ; \mathrm{H}=1 \mathrm{u})$$

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

$$\left(N_A=6.02 \times 10^{23}\right)$$