Chapter 22

The empirical formula of a compound is \(\mathrm{CH}_{2}\). One mole of the compound has a mass of \(42 \mathrm{~g}\). Its molecular formula is (a) \(\mathrm{C}_{3} \mathrm{H}_{6}\) (b) \(\mathrm{C}_{3} \mathrm{H}_{8}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{2}\) (d) \(\mathrm{CH}_{2}\)

In the estimation by Duma's method, \(0.59 \mathrm{~g}\). of an organic compound gave \(112 \mathrm{~mL}\) nitrogen at NTP. The percentage of nitrogen in the compound is about (a) \(23.7\) (b) \(16.8\) (c) \(33.07\) (d) \(27.5\)

\(60 \mathrm{~g}\) of a compound on analysis produced \(24 \mathrm{~g}\) carbon, \(4 \mathrm{~g}\) hydrogen and \(32 \mathrm{~g}\) oxygen. The empirical formula of the compound is (a) \(\mathrm{CH}_{4} \mathrm{O}\) (b) \(\mathrm{CH}_{2} \mathrm{O}_{2}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}\) (d) \(\mathrm{CH}_{2} \mathrm{O}\)

Mark the incorrect statement in Kjeldahl's method of estimation of nitrogen (a) copper sulphate or mercury acts as a catalyst (b) nitrogen is quantitatively decomposed to give ammonium sulphate (c) nitrogen gas is collected over caustic potash solution (d) potassium sulphate is used as boiling point elevator of \(\mathrm{H}_{2} \mathrm{SO}_{4}\)

An organic compound is found to have the formula \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{ONCl}\). The percentage of nitrogen present in it is (a) \(23.36 \%\) (b) \(10.3 \%\) (c) \(41.05 \%\) (d) \(5.06 \%\)

The empirical formula of a compound is \(\mathrm{CH}_{2}\). One mole of the compound has a mass of \(42 \mathrm{~g}\), its molec \(-\) ular formula is (a) \(\mathrm{C}_{2} \mathrm{H}_{2}\) (b) \(\mathrm{C}_{2} \mathrm{H}_{4}\) (c) \(\mathrm{C}_{3} \mathrm{H}_{\mathrm{s}}\) (d) \(\mathrm{C}_{4} \mathrm{H}_{8}\)

Sorbic acid consists of \(\mathrm{C}=64.3 \%, \mathrm{H}=7.2 \%\) and \(28.5 \%\) oxygen. Find the empirical formula. (a) \(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}\) (b) \(\mathrm{C}_{3} \mathrm{H}_{4} \mathrm{O}_{2}\) (c) \(\mathrm{C}_{3} \mathrm{H}_{4} \mathrm{O}\) (d) \(\mathrm{CH}_{2} \mathrm{O}\)

A mixture contains four solid organic compounds \((\mathrm{A}),(\mathrm{B}),(\mathrm{C})\) and (D). On heating, only (C) changes from solid to vapour state. The compound (C) can be separated from the mixture by (a) sublimation (b) crystallization (c) distillation (d) fractional distillation

\(0.24 \mathrm{~g}\) of a volatile liquid on vaporization gives \(45 \mathrm{~mL}\) of vapours at STP. What will be the vapour density of the substance? (Density of \(\mathrm{H}_{2}=0.089 \mathrm{gL}^{-1}\) ) (a) \(99.39\) (b) \(39.95\) (c) \(95.53\) (d) \(59.93\)

If a compound on analysis was found to contain \(\mathrm{C}=\) \(18.5 \%, \mathrm{H}=1.55 \%, \mathrm{Cl}=55.04 \%\) and \(\mathrm{O}=24.81 \%\) then its empirical formula is (a) \(\mathrm{CHClO}\) (b) \(\mathrm{CH}_{2} \mathrm{ClO}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OCl}\) (d) \(\mathrm{ClC}_{2} \mathrm{H}_{5} \mathrm{O}\)

A compound with empirical formula \(\mathrm{CH}_{2} \mathrm{O}\) has a vapour density of 30 . Its molecular formula is (a) \(\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}_{3}\) (b) \(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{2} \mathrm{O}_{2}\) (d) \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\)

The identity of two different solid organic compounds having the same melting point can be best ascertained by determining their (a) dipole moment (b) solubility (c) melting point of their \(1: 1\) mixture (d) refractive indices

\(0.5 \mathrm{~g}\) of an organic compound in Kjeldahl experiment needs \(29 \mathrm{ml}\) of \(\frac{\mathrm{N}}{5} \mathrm{H}_{2} \mathrm{SO}_{4}\) for complete neutralisation of \(\mathrm{NH}_{3} .\) The \(\mathrm{N} \%\) is? (a) \(16.2\) (b) \(8.1\) (c) \(24.3\) (d) \(32.4\)

When \(0.25 \mathrm{~g}\) of an organic compounds is heated with \(\mathrm{HNO}_{3}\) and \(\mathrm{AgNO}_{3}\) in a carius tube, it gives \(0.35 \mathrm{~g}\) of silver chloride. The percentage of chlorine in the compound is (a) \(36.6 \%\) (b) \(45.3 \%\) (c) \(34.6 \%\) (d) \(54.8 \%\)

The empirical formula of a compound is \(\mathrm{CH}_{2} \mathrm{O}\). If \(0.0832\) mole of the compound contains \(1.0 \mathrm{~g}\) of hydrogen, then the molecular formula of the compound is (a) \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\) (b) \(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\) (c) \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{5}\) (d) \(\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}_{3}\)

\(0.765 \mathrm{~g}\) of an acid gives \(0.535 \mathrm{~g}\) of \(\mathrm{CO}_{2}\) and \(0.14 \mathrm{~g}\) of \(\mathrm{H}_{2} \mathrm{O} .\) Then the ratio of the percentage of carbon and hydrogen is (a) \(1: 9\) (b) \(20: 16\) (c) \(18: 11\) (d) \(19: 2\)

\(5.0 \mathrm{~g}\) of a certain metal, \(\mathrm{X}\) (atomic mass \(=27\) ) is converted into \(61.7 \%\) crystalline sulphate containing \(48.6 \%\) by mass of water of crystallization. The simplest formula of the compound is (a) \(\mathrm{X}_{2}\left(\mathrm{SO}_{4}\right)_{3} \cdot 18 \mathrm{H}_{2} \mathrm{O}\) (b) \(\mathrm{X}_{2}\left(\mathrm{SO}_{4}\right)_{3} \cdot 14 \mathrm{H}_{2} \mathrm{O}\) (c) \(\mathrm{X}_{2}\left(\mathrm{SO}_{4}\right)_{3} \cdot 16 \mathrm{H}_{2} \mathrm{O}\) (d) \(\mathrm{X}_{2}\left(\mathrm{SO}_{4}\right)_{3} \cdot 12 \mathrm{H}_{2} \mathrm{O}\)

If \(0.2\) gram of an organic compound containing carbon, hydrogen and oxygen, on combustion, yielded \(0.147\) gram carbon dioxide and \(0.12\) gram water. What will be the content of oxygen in the substance? (a) \(73.29 \%\) (b) \(68.45 \%\) (c) \(85.23 \%\) (d) \(89.50 \%\)

Using Victor Meyer's method, \(0.2 \mathrm{~g}\) of an organic substance displaced \(56 \mathrm{~mL}\) of air at STP. The molecular weight of the compound is (a) 112 (b) 56 (c) 80 (d) 28

What is the molecular formula of a compound, whose empirical formula is \(\mathrm{CH}_{2} \mathrm{O}\) and molecular weight is \(90 ?\) (a) \(\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O}_{2}\) (b) \(\mathrm{C}_{6} \mathrm{H}_{6} \mathrm{O}_{3}\) (c) \(\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}_{3}\) (d) \(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{O}_{4}\)

An organic compound has \(\mathrm{C}\) and \(\mathrm{H}\) percentage in the ratio \(6: 1\) and \(\mathrm{C} \%\) and \(\mathrm{O} \%\) in the ratio \(3: 4\). The compound is (a) HCHO (b) \(\mathrm{CH}_{3} \mathrm{OH}\) (c) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}\) (d) \((\mathrm{COOH})_{2}\)

A complex compound of cobalt with the composition \(\mathrm{Co}=22.58 \%, \mathrm{H}=5.79 \%, \mathrm{~N}=32.2 \%, \mathrm{O}=12.20 \%\) and \(\mathrm{Cl}=27.17 \%\) on heating, looses ammonia to the extent of \(32.63 \%\) of its mass. The number of molecules of ammonia present in one molecule of the cobalt complex is (At. mass of \(\mathrm{Co}=58.9\) ) (a) 7 (b) 5 (c) 8 (d) 12

In the enzyme peroxidase anhydrase the percentage of selenium (Se) by mass is \(0.5 \%\). If atomic mass of Se is \(78.4 \mathrm{U}\), then minimum molecular mass of peroxidase anhydrase enzyme is (a) \(1.568 \times 10^{3} \mathrm{U}\) (b) \(1.568 \times 10^{4} \mathrm{U}\) (c) \(1.568 \mathrm{U}\) (d) \(2.136 \times 10^{4} \mathrm{U}\)

A gaseous hydrocarbon has \(85 \%\) carbon and vapour density of 28 . The possible formula of the hydrocarbon will be (a) \(\mathrm{C}_{4} \mathrm{H}_{\mathrm{s}}\) (b) \(\mathrm{C}_{2} \mathrm{H}_{4}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{2}\) (d) \(\mathrm{C}_{3} \mathrm{H}_{6}\)

An organic compound contains \(49.3 \%\) carbon, \(6.84 \%\) hydrogen and its vapour density is 73. Molecular formula of the compound is (a) \(\mathrm{C}_{3} \mathrm{H}_{10} \mathrm{O}_{2}\) (b) \(\mathrm{C}_{3} \mathrm{H}_{5} \mathrm{O}_{2}\) (c) \(\mathrm{C}_{6} \mathrm{H}_{10} \mathrm{O}_{8}\) (d) \(\mathrm{C}_{4} \mathrm{H}_{10} \mathrm{O}_{2}\)

An organic compound has \(\mathrm{C}\) and \(\mathrm{H}\) percentage in the ratio \(6: 1\) and \(\mathrm{C}\) and \(\mathrm{O}\) percentage in the \(3: 4\). The compound is (a) \((\mathrm{COOH})_{2}\) (b) \(\mathrm{CH}_{3} \mathrm{OH}\) (c) \(\mathrm{HCHO}\) (d) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}\)

An organic compound containing carbon, hydrogen and oxygen contains \(52.2 \%\) carbon and \(13.04 \%\) hydrogen. Vapour density of the compound is \(23 .\) Its molecular formula will be (a) \(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{O}\) (b) \(\mathrm{C}_{3} \mathrm{H}_{8} \mathrm{O}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O}\) (d) \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}\)

On combustion, \(0.2 \mathrm{~g}\) of an organic compound containing carbon, hydrogen and oxygen yields \(0.147\) g carbon dioxide and \(0.12 \mathrm{~g}\) water. The percentage of carbon, hydrogen and oxygen respectively in the compound is (a) \(22.5,8.7\) and \(68.8\) (b) \(20,6.7\) and \(73.3\) (c) \(18.2,9.5\) and \(72.3\) (d) \(28.9,12.8\) and \(58.8\)

Which of the following pair of compounds can be separated by using fractional distillation (a) Acetone and methyl alcohol (b) Benzene and toluene (c) Ethyl alcohol (95.5\%) and water \((4.5 \%)\) (d) Crude petroleum (gasoline and kerosene)

Select the correct statements regarding Lassaigne's test? (a) Li and \(K\) are not used in this test (b) \(\mathrm{NH}_{4} \mathrm{Cl}, \mathrm{NH}_{2}-\mathrm{NH}_{2}\) Can't be detected by this test. (c) Urea, Acetamide can not give this test. (d) Benzamide, Azobenzene can give this test.

In the detection of ' \(\mathrm{N}\) ' by Lassaigne's test which of the following compounds are formed during this test? (a) \(\mathrm{Fe}(\mathrm{OH})_{2}\) (b) \(\mathrm{Na}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]\) (c) \(\mathrm{FeCl}_{3}\) (d) \(\left.\mathrm{Fe}_{4}[\mathrm{Fe}(\mathrm{CN})]_{3}\right]\)

Kjeldohl's method can not be used to detect \(96 \%\) of \(\mathrm{N}\) in which of these compounds? (a) Pyridine (b) Pyrole (c) Aniline (d) Diazo compounds

\(0.189 \mathrm{gm}\) of an organic compound gives \(0.287 \mathrm{~g}\) of \(\mathrm{AgCl}\). The \(\%\) of \(\mathrm{Cl}\) in it is? (a) \(18.75 \%\) (b) \(37.56 \%\) (c) \(55.25\) (d) \(74 \%\)

In Carius method sodium extract is boiled with \(\mathrm{HNO}_{3}\) it is for (a) To decompose \(\mathrm{NaCN}\) into \(\mathrm{HCN}(\mathrm{g})\) (b) To decompose \(\mathrm{Na}_{2} \mathrm{~S}\) into \(\mathrm{H}_{2} \mathrm{~S}(\mathrm{~g})\) (c) To neutralise free alkali (d) all of these

Match the following Column-I (Method used for detections) (a) Liebig's method (b) Duma's method (c) Carius method (d) Kjeldahl's method Column-II (Element detections) (p) Carbon 1 \(P\) (q) Nitrogen ) ( (r) Sulphur 3 (s) Hydrogen (t) Halogen

Kjeldahl method can not be used to detect \(\mathrm{N} \%\) in which of the following compounds \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{~N}, \mathrm{C}_{4} \mathrm{H}_{5} \mathrm{~N}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NO}_{2}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}\) Pyridine Pyrole \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{~N}_{2}^{+} \mathrm{Cl} \mathrm{Ph}-\mathrm{N}=\mathrm{N}-\mathrm{Ph},\left(\mathrm{CH}_{3}\right)_{2} \mathrm{NH}, \mathrm{CH}_{3} \mathrm{CN}\)

How many of the following elements can be tested by using Lassaigne's Test. \(\mathrm{N}, \mathrm{S}, \mathrm{Cl}, \mathrm{Br}, \mathrm{I}, \mathrm{O}, \mathrm{C}, \mathrm{P}, \mathrm{H}\)

\(0.1 \mathrm{~g}\) of an organic monobasic acid on complete combustion gave \(0.254 \mathrm{~g} \mathrm{CO}_{2}\) and \(0.0443 \mathrm{~g} \mathrm{H}_{2} \mathrm{O}\). For complete neutralisation \(0.122 \mathrm{~g}\) of the acid requires \(10 \mathrm{ml}\) of \(0.1 \mathrm{~m} \mathrm{KOH}\). The molecular formula of the acid is \(\mathrm{C}_{\mathrm{x}} \mathrm{H}_{6} \mathrm{O}_{2}\) the value of ' \(\mathrm{X}^{\prime}\) is?

In an organic compound of molar mass \(108 \mathrm{~g} \mathrm{~mol}^{-1} \mathrm{C}\), \(\mathrm{H}\) and \(\mathrm{N}\) atoms are present in \(9: 1: 3.5\) by weight. The molecular formula of the compound can be (a) \(\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{~N}_{2}\) (b) \(\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{~N}_{2}\) (c) \(\mathrm{C}_{5} \mathrm{H}_{6} \mathrm{~N}_{3}\) (d) \(\mathrm{C}_{4} \mathrm{H}_{12} \mathrm{~N}_{2}\)

Bottles containing \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{I}\) and \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{I}\) lost their original labels. They were labeled \(\mathrm{A}\) and \(\mathrm{B}\) for testing. A and B were separately taken in test tubes and boiled with \(\mathrm{NaOH}\) solution. The end solution in each tube was made acidic with dilute \(\mathrm{HNO}_{3}\) and some \(\mathrm{AgNO}_{3}\) solution added. Solution B gave a yellow precipitate. Which one of the following statements is true for the experiment? (a) \(\mathrm{A}\) was \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{I}\) (b) A was \(\mathrm{C}_{6} \mathrm{H}_{6} \mathrm{I}\) (c) B was \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{I}\) (d) addition of \(\mathrm{HNO}_{3}\) was unnecessary

The ammonia evolved from the treatment of \(0.30 \mathrm{~g}\) of an organic compound for the estimation of nitrogen was passed in \(100 \mathrm{~mL}\) of \(0.1 \mathrm{M}\) sulphuric acid. The excess of acid required \(20 \mathrm{~mL}\) of \(0.5 \mathrm{M}\) sodium hydroxide solution for complete neutralization. The organic compound is (a) benzamide (b) acetamide (c) thiourea (d) urea

The compound formed in the positive test for nitrogen with the Lassaigne solution of an organic compound is (a) \(\mathrm{Fe}(\mathrm{CN})\), (b) \(\mathrm{Fe}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]_{3}\) (c) \(\mathrm{Na}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{5} \mathrm{NOS}\right]\) (d) \(\mathrm{Na}_{3}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]\)

An organic compound having molecular mass 60 is found to contain \(\mathrm{C}=20 \%, \mathrm{H}=6.67 \%\) and \(\mathrm{N}=\) \(46.67 \%\) while rest is oxygen. On heating, it gives \(\mathrm{NH}_{3}\) along with a solid residue. The solid residue give violet colour with alkaline copper sulphate solution. The compound is (a) \(\mathrm{CH}_{3} \mathrm{CONH}_{2}\) (b) \(\mathrm{CH}_{3} \mathrm{NCO}\) (c) \(\left(\mathrm{NH}_{2}\right)_{2} \mathrm{CO}\) (d) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CONH}_{2}\)

\(29.5 \mathrm{mg}\) of an organic compound containing nitrogen was digested according to Kjeldahl's method and the evolved amomnia was absorbed in \(20 \mathrm{~mL}\) of \(0.1 \mathrm{M} \mathrm{HCl}\) solution. The excess of the acid required \(15 \mathrm{~mL}\) of \(0.1 \mathrm{M} \mathrm{NaOH}\) solution for complete neutralization. The percentage of nitrogen in the compound is (a) \(59.0\) (b) \(47.4\) (c) \(23.7\) (d) \(29.5\)

For the estimation of nitrogen, \(1.4 \mathrm{~g}\) of an organic compound was digested by Kjeldahl method and the evolved ammonia was absorbed in \(60 \mathrm{~mL}\) of \(\frac{\mathrm{M}}{10}\) sulphuric acid. The unreacted acid required \(20 \mathrm{~mL}\) of \(\frac{\mathrm{M}}{10}\) sodium hydroxide for complete neutralizaton. The percentage of nitrogen in the compound is: (a) \(3 \%\) (b) \(5 \%\) (c) \(6 \%\) (d) \(10 \%\)

In Carius method of estimation of halogens, \(250 \mathrm{mg}\) of an organic compound gave \(141 \mathrm{mg}\) of \(\mathrm{AgBr}\). The percentage of bromine in the compound is (At. mass \(\mathrm{Ag}=108 ; \mathrm{Br}=80)\) (a) \(24 \%\) (b) \(36 \%\) (c) \(48 \%\) (d) \(60 \%\)

Glycerol can be separated from spent bye by using (a) Steam Distillation (b) Vaccum Distillation (c) Fractional Distillation (d) Distillation under Reduced Pressure