Some Basic Concepts of Chemistry · Chemistry · AP EAPCET
MCQ (Single Correct Answer)
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 N acid solution respectively are
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 $\mathrm{H}_2 \mathrm{O}(l)$. What is the mole fraction of $\mathrm{C}_2 \mathrm{H}_4$ in the mixture ?
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 end of the reaction?
Consider the following
(A) 0.0025
(B) 500.0
(C) 2.0034
Number of significant figures in $A, B$ and $C$ respectively, are
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
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.
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.
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
$$ \left(N_A=6.02 \times 10^{23}\right) $$
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 ?
$$ (\mathrm{N}=14 \mathrm{u} ; \mathrm{O}=16 \mathrm{u} ; \mathrm{H}=1 \mathrm{u}) $$
The concentration of 1 L of $\mathrm{CaCO}_3$ solution is 1000 ppm . What is its concentration in mol $\mathrm{L}^{-1}$ ?
$$ (\mathrm{Ca}=40 \mathrm{u}, \mathrm{O}=16 \mathrm{u}, \mathrm{C}=12 \mathrm{u}) $$
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 empirical formula of calgon is
The statement related to law of definite proportions is
What are $$x$$ and $$y$$ in the following reaction?
$$x \mathrm{~Pb}_3 \mathrm{O}_4 \longrightarrow y \mathrm{PbO}+\mathrm{O}_2$$
If the volume of $$15.9 \mathrm{~g}$$ of carbon tetrachloride is $$10 \mathrm{~mL}$$, calculate its density.
$$0.63 \mathrm{~g}$$ of oxalic acid is dissolved in order to obtain $$250 \mathrm{~cm}^3$$ of its solution. Find the normality of this solution. [oxalic acid $$\left.(\mathrm{COOH})_2 \cdot 2 \mathrm{H}_2 \mathrm{O}\right]$$
$$7.8 \mathrm{~g}$$ 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)
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 ?
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