Percentage Composition

Q.

How do you prepare a $1\mathrm{M}$ $\mathrm{HCl}$ solution, which has a specific gravity of $1.18$? The HCl solution has $35\%$ purity. Calculate the volume required to prepare the solution.

Q. In the reaction, $2S{O}_2\left(g\right)+O_2\left(g\right)\to 2S{O}_3\left(g\right),$ when 1 mole of $S{O}_2$ and 1 mole of $O_2$ are made to react to completion:

1. 0.5 mole of $S{O}_2$ is remained
2. All of these
3. All the oxygen will be consumed
4. 1.0 mole of $S{O}_3$ will be produced

Q. If potassium chlorate is $80\%$ pure then $48g$ of oxygen would be produced from (atomic mass of $K=39u$)

1. $153.12g$ of $KCl{O}_3$
2. $245g$ of $KCl{O}_3$
3. $98.0g$ of $KCl{O}_3$
4. $122.5g$ of $KCl{O}_3$

Q. In a reaction, 358 g of $TiC{l}_4$ is reacted with 96 g of Mg. Calculate the % yield of $Ti$ if 32 g of $Ti$ is obtained from the reaction. (Molar mass of $Ti$ = 48 g/mol, Mg = 24 g/mol)

1. 35.46%
2. 66.86%
3. 85.76%
4. 48.34%

Q.

Determine the Vant Hoff factor for$\mathrm{Ca}{\left({\mathrm{NO}}_3\right)}_2$ on complete (100%) dissociation.

Q. What is the % of $H_{2}O$ in $Fe(CNS{)}_3.3H_{2}O$

1. 30
2. 19
3. 25
4. 45

Q. The percentage of phosphorus in $H_{3}P{O}_4$ is:

1. $22.22\%$
2. $45\%$
3. $28.57\%$
4. $31.63\%$

Q. Carbon tetrachloride $\left(CC{l}_4\right)$ is mixed in 390 g of benzene to make a solution for supporting an organic chemical reaction in which mole fraction of benzene is 0.91. Find the molality of the $CC{l}_4$ solution.

1. $4.25\text{m}$
2. $1.26\text{m}$
3. $2.67\text{m}$
4. $4.44\text{m}$

Q. The crystalline salt $N{a}_{2}S{O}_4.x{H}_{2}O$ on heating loses 55.9% of its mass and becomes anhydrous. The formula of the crystalline salt is:

1. $N{a}_{2}S{O}_4.5H_{2}O$
2. $N{a}_{2}S{O}_4.7H_{2}O$
3. $N{a}_{2}S{O}_4.2H_{2}O$
4. $N{a}_{2}S{O}_4.10H_{2}O$

Q. What volume of air at $1$ atm and $273\text{K}$ that has 21% of oxygen by volume is required to completely burn sulphur $\left(S_8\right)$ present in $200\text{g}$ of a sample, which contains 20% inert material that does not burn? Sulphur burns according to the reaction:
$\frac{1}{8}{S}_8\left(s\right)+O_2\left(g\right)\to S{O}_2\left(g\right)$

1. 533.3 litre
2. 23.52 litre
3. 320.0 litre
4. 112.0 litre

Q. The fixing of photographic plate film involves dissolution of unexposed silver bromide in hypo solution according to the equation that follows.
$AgBr\left(s\right)+2S_2{O}_3^{2-}\left(eq\right)\rightleftharpoons Ag\left(S_2{O}_3{)}_2^{3-}\right(aq)+B{r}^{-}(aq)$. If the molar solubility of $AgBr$in a 0.1 M hypo solution assuming its complete dissociation, is $4.3\times {10}^{-x}$. Then find the value of $x$.
$K_{sp}$ of $AgBr=4.5\times {10}^{-13}$
$K_f$ of $Ag(S_2{O}_3{)}_2^{3-}=2.0\times {10}^{13}$

Q.

Which of the following compounds contains the highest percentage of nitrogen?

(a) Ca (NO₃)₂

(b) CaCN₂

(c) (NH₄)₂SO₄

(Ca=40, N=14, O=16.C=12, H=1, S=32)

Q. In a small-scale experiment, 10 g of $KCl{O}_3$ was carefully decomposed and 3.41 g of $O_2$ gas was collected. What are the theoretical(g), actual(g) and percent (%) yields of the reaction?

1. 3.41 g, 3.92 g, 87%
2. 5.57 g, 6.12 g, 68 %
3. 3.92 g, 3.41 g, 87 %
4. 6.59 g, 3.41 g, 34 %

Q. Mole fraction is represented by.

1. m
2. f
3. $\chi$
4. m.f.

Q. X and Y are two compounds of elements A and Cl. Molar mass and mass % of Cl are given in the table below.
$\begin{array}{ccc}\text{Compound}& \text{Molar mass}& \%\text{of Cl}\\ X& 137& 77.5\\ Y& 208& 85.1\end{array}$

Thus, X and Y are:

1. $AC{l}_3,AC{l}_5$
2. $A_{2}C{l}_3,AC{l}_3$
3. $ACl,AC{l}_2$
4. $AC{l}_3,AC{l}_4$

Q. Calculate the percentage of sulphur present in sulphuric acid $\left(H_{2}S{O}_4\right)$.

1. 68.35
2. 32.65
3. 60
4. 40

Q. An alloy of iron (54.7%), nickel (45%) and manganese (0.3%) has a density of $8.17{\text{g/cm}}^3$. How many iron atoms are present in a block of the alloy measuring $10\text{cm}\times 20\text{cm}\times 15\text{cm}$?

1. $1.422\times {10}^{26}$
2. $1.422\times {10}^{23}$
3. $6.23\times {10}^{23}$
4. $1.656\times {10}^{26}$

Q. Equal weights of X and Y are reacted to form the compound $X_2{Y}_3$. Which of the following statements holds true?
(Molar mass of X = 36 g/mol, molar mass of Y = 24 g/mol)

1. X is the limiting reagent
2. No reactant is left over and mass of $X_2{Y}_3$ formed is double the mass of ‘X’ taken
3. Y is the limiting reagent
4. None of these

Q. $1g$ of an alloy of aluminum and magnesium when treated with excess of dil.HCl form magnesium chloride and aluminium chloride and hydrogen collected over mercury at $0^{o}C$ has a volume of $1.20L$ at $0.92$ atmospheric pressure. The composition of alloy is:

1. $Al=54.86\%$ and $Mg=45.14\%$
2. $Mg=54.86\%$ and $Al=45.14\%$
3. $Al=45.86\%$ and $Mg=54.14\%$
4. $Al=45.68\%$ and $Mg=54.32\%$

Q. Butyric acid contains only C, H and O. A 4.24 mg sample of butyric acid is completely burned. It gves 8.45 mg of carbon dioxide $\left(C{O}_2\right)$ and 3.46 mg of water. What is the mass percentage of C, H and O in butyric acid respectively?

1. $54.35,9.06,36.59$
2. $36.59,54.35,9.06$
3. $54.35,36.59,9.06$
4. $9.06,54.35,36.59$

Q. In a reaction, 358 g of $TiC{l}_4$ is reacted with 96 g of Mg. Calculate the % yield of $Ti$ if 32 g of $Ti$ is obtained from the reaction. (Molar mass of $Ti$ = 48 g/mol, Mg = 24 g/mol)

1. 35.46%
2. 66.86%
3. 85.76%
4. 48.34%

Q. Two metallic oxides contain 27.6 % and 30 % oxygen respectively. If the formula of the first oxide is $X_3{O}_4$, what will be the formula of the second oxide?

1. $XO$
2. $X_2{O}_3$
3. $X_2{O}_5$
4. $X{O}_2$

Q. Given that the abundance of isotopes ${}^{54}Fe{,}^{56}Fe,$ and ${}^{57}Fe$ is 5%, 90% and 5%, respectively. The atomic mass of Fe is
(IIT-JEE, 2009)

1. 55.85
2. 55.95
3. 55.75
4. 55.05

Q.

Reaction	Yield of the reaction
$\left(i\right)2A+3B\to 3C+D$	80%
$\left(ii\right)2C+E\to 4F$	40 %
$\left(iii\right)3F+7H\to 8G$	50%

Starting with 6 mol of A, 9 mol of B, 4 mol of E and 15 mol of H, the number of moles of G formed will be

1. 4.48 mol
2. 7.68 mol
3. 5.28 mol
4. 6.68 mol

Q. An organic compound containing $C$ and $H$ gave the following analysis: $C=40\%,H=6.7\%$ and the remaining, oxygen. Its empirical formula would be:

1. $C{H}_4$
2. $C{H}_{2}O$
3. $C_2{H}_{3}O$
4. $C_2{H}_4$

Q. A $10.0\text{g}$ sample of a mixture of calcium chloride and sodium chloride is treated with a $N{a}_{2}C{O}_3$ solution. This calcium carbonate is heated to convert all the calcium to calcium oxide and the final mass of the calcium oxide is $1.62\text{g}$. The percentage by mass of calcium chloride in the original mixture is:

1. 15.2 %
2. 32.1 %
3. 21.8 %
4. 11.07 %

Q. Calculate the amount of $CaC{O}_3$ in grams having percentage purity $25\%$ that produces $0.56$ litre of $C{O}_2$ at STP on heating?

Q. $200g$ of a calcium carbonate sample decomposes on heating to give carbon dioxide and $80g$ of calcium oxide. What will be the percentage purity of calcium carbonate in the sample?
($Given:CaC{O}_3\to CaO+C{O}_2$)

1. $58.14\%$
2. $71.43\%$
3. $84.33\%$
4. $28.89\%$

Q. The weight percentage of carbon in carbon dioxide and carbon disulphide is 27.27% and 15.79% respectively. What is the ratio of $S$ and $O$ that can combine with same weight of carbon?

1. $2:1$
2. $1:2$
3. $1:1$
4. $1:3$

Q. The mass percentage of nitrogen in urea ($N{H}_{2}CON{H}_2$) is .

1. 85
2. 47
3. 18
4. 28