Chapter 22

The most satisfactory method to separate sugar is to use (a) sublimation (b) fractional crystallization (c) Benedict's reagent (d) chromatography

The compound that does not give a blue colour in Lassaigne's test is (a) aniline (b) glycine (c) hydrazine (d) urea

Impure glycerine is purified by (a) vacuum distillation (b) simple distillation (c) steam distillation (d) none of the above

When pieces of human hair are heated strongly with soda-lime, smell of ammonia can be detected. Which one of the following conclusion can be drawn from this observation? (a) hair contains amino acids (b) ammonium salt is present in hair (c) ammonia is present in the human hair (d) none of the above

Nitrogen in an organic compound can be estimated by (a) Duma's method only (b) Kjeldahl's method only (c) both (a) and (b) (d) none of these

In Lassaigne's test for nitrogen, the blue colour is due to the formation of (a) ferriferrocyanide (b) sodium cyanide (c) potassium fericyanide (d) sodium ferrocyanide

Carbon and hydrogen are estimated by (a) Leibig method (b) Duma's method (c) Carius method (d) Kjeldahl's method

Aniline is usually purified by (a) chromatography technique (b) by addition of oxalic acid (c) fractional crystallization (d) steam distillation

In Kjeldhal's method, nitrogen present is estimated as (a) NO (b) \(\mathrm{NH}_{3}\) (c) \(\mathrm{NO}_{2}\) (d) \(\mathrm{N}_{2}\)

Molecular mass of a volatile substance may be obtained by (a) Liebig's method (b) Kjeldhal's method (c) Duma's method (d) Victor Meyer's method

Which of the following compounds does not show Lassaigne's test for nitrogen? (a) urea (b) azobenzene (c) hydrazine (d) phenylhydrazine

In a hydrocarbon, mass ratio of hydrogen and carbon is \(1: 3\), the empirical formula of hydrocarbon is (a) \(\mathrm{CH}_{2}\) (b) \(\mathrm{CH}_{4}\) (c) \(\mathrm{CH}_{3}\) (d) \(\mathrm{CH}\)

A mixture of benzene and chloroform is separated by (a) sublimation (b) separation funnel (c) crystallization (d) distillation

Which method is used for the separation of two immiscible liquids? (a) chromatography (b) fractionating column (d) fractional distillation (c) separating funnel

The empirical formula of an acid is \(\mathrm{CH}_{2} \mathrm{O}_{2}\), the probable molecular formula of the simplest acid may be (a) \(\mathrm{CH}_{2} \mathrm{O}\) (b) \(\mathrm{CH}_{2} \mathrm{O}_{2}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}\) (d) \(\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}_{4}\)

During formation of sodium extract, generally the substance that ignites is (a) \(\mathrm{Na}\) (b) \(\mathrm{O}_{2}\) (c) \(\mathrm{CO}_{2}\) (d) \(\mathrm{H}_{2}\)

The equivalent mass of an acid is equal to (a) molecular mass \(\times\) acidity (b) molecular mass \(\times\) basicity (c) molecular mass/acidity (d) molecular mass/basicity

Fractional distillation is used to separate liquids which differ in their boiling points by (a) \(5^{\circ} \mathrm{C}\) (b) \(10^{\circ} \mathrm{C}\) (c) \(30^{\circ} \mathrm{C}-80^{\circ} \mathrm{C}\) (d) Less than \(20^{\circ} \mathrm{C}\)

Thiophene can be removed from commercial benzene by (a) steam distillation (b) shaking with conc. \(\mathrm{H}_{2} \mathrm{SO}_{4}\) (c) shaking with NaOH solution (d) shaking with ether

The Beilstein test for organic compounds is used to detect (a) nitrogen (b) sulphur (c) carbon (d) halogens

Which of the following is the best scientific method to test presence of water in a liquid? (a) taste (b) smell (c) use of litmus paper (d) use of anhydrous copper sulphate.

Which of the following has high vapour pressure at temperature below its melting point? (a) benzoic acid (b) citric acid (c) salicylic acid (d) all

When petroleum is heated gradually, first batch of vapours evolved will be rich in (a) kerosene (b) petroleum ether (c) diesel (d) lubricating oil

Absolute alcohol is prepared by (a) fractional distillation (b) Kolbe's method (c) vacuum distillation (d) azeotropic distillation

In paper chromatography, (a) mobile phase is liquid and stationary phase is solid (b) mobile phase is solid and stationary phase in solid (c) mobile phase is liquid and stationary phase is liquid (d) mobile phase is solid and stationary phase is liquid.

Azeotropic mixture of two liquids can be separated by (a) azeotropic distillation (b) fractional distillation (c) simple distillation (d) steam distillation

A mixture of benzoic acid and naphthalene can be separated by crystallization from (a) cold water (b) ether (c) hot water (d) benzene

Aniline is insoluble in water and possesses a vapour pressure of \(10-15 \mathrm{~mm} \mathrm{Hg}\) at \(373 \mathrm{~K}\). It can be conveniently purified by (a) simple distillation (b) steam distillation (c) crystallization (d) sublimation

Which of the following compound will not produce a white precipitate of \(\mathrm{AgCl}\) on warming with ethanolic silver nitrate solution? (a) \(\mathrm{CH}_{3}-\mathrm{CH}_{2} \mathrm{Cl}\) (b) \(\mathrm{CH}_{2}=\mathrm{CHCH}_{2} \mathrm{Cl}\) (c) ClCc1ccccc1 (d) Clc1ccccc1

In Kjeldahl's method of estimation of nitrogen, \(\mathrm{K}_{2} \mathrm{SO}_{4}\) acts as (a) catalytic agent (b) boiling point elevator (c) hydrolysis agent (d) oxidizing agent

There is no direct test for the detection of which of the following when present in an organic compound? (a) \(\mathrm{Cl}\) (b) \(\mathrm{O}\) (c) \(\underline{S}\) (d) \(\mathrm{N}\)

Liquids which decompose below their normal boiling points can be distilled at lower temperature by (a) decreasing the pressure (b) heating in sand bath (c) increasing the pressure (d) heating in water bath

Separation of two substances by fractional crystallization depends upon their difference in. (a) viscosity (b) density (c) solubility (d) crystalline shape

Lassaigne's test for the detection of nitrogen will fail in case of (a) \(\mathrm{C}_{6} \mathrm{H}_{3} \mathrm{NHNH}_{2}, 2 \mathrm{HCl}\) (b) \(\mathrm{H}_{2} \mathrm{~N} \cdot \mathrm{NH}_{2}, 2 \mathrm{HCl}\) (c) \(\mathrm{NH}_{2} \mathrm{CONH}_{2}\) (d) \(\mathrm{H}_{2} \mathrm{NCONHNH}_{2} \mathrm{HCl}\)

Absolute alcohol cannot be obtained by simple fractionation of a solution of water and alcohol because (a) ethanol molecules are solvated (b) boiling points are very near (c) ethanol remains dissolved in water (d) they form a constant boiling mixture

In steam distillation, the vapour pressure of the volatile organic compound is (a) more than atmospheric pressure (b) equal to atmospheric pressure (c) less than atmospheric pressure (d) none of these

The purity of organic compounds is determined by (a) mixed melting point (b) molecular weight (c) melting point (d) density

In Kjeldahl's method of estimation of nitrogen, copper sulphate acts as (a) catalytic agent (b) silver spiral (c) hydrolyzing agent (d) oxidizing agent

An organic dibasic acid is used in volumetric analysis. The percentage of elements are \(\mathrm{C}=26.7 \%\), \(\mathrm{H}=2.2 \%\) and \(\mathrm{O}=71.1 \%\). Find the empirical formula of the acid. (a) \(\mathrm{CH}_{2} \mathrm{O}\) (b) \(\mathrm{CHO}_{2}\) (c) \(\mathrm{C}_{2} \mathrm{H}_{2} \mathrm{O}_{2}\) (d) \(\mathrm{CH}_{4} \mathrm{O}\)

The molecular formula weight by empirical formula weight of a compound is 3. The empirical formula is \(\mathrm{CH}_{2}\). The vapour density of the compound is (a) 21 (b) \(11.5\) (c) 33 (d) 43

Chromatographic technique is used for these paration of (a) plant pigments (b) dye stuffs (c) small samples of mixtures (d) all of these

For a diacidic base, the molecular weight is 82 . The weight of chloroplatinate is \(0.984 \mathrm{~g}\). The weight of platinum is (a) \(0.39\) (b) \(0.68\) (c) \(7.8\) (d) \(1.8\)

A dibasic acid containing \(\mathrm{C}, \mathrm{H}\) and \(\mathrm{O}\) was found to contain \(\mathrm{C}=26.7 \%\) and \(\mathrm{H}=2.2 \%\). The vapour density of diethyl ester of the acid was found to be \(73 .\) What is the molecular formula of the acid? (a) \(\mathrm{CH}_{2} \mathrm{O}_{2}\) (b) \(\mathrm{C}_{2} \mathrm{H}_{2} \mathrm{O}_{4}\) (c) \(\mathrm{C}_{3} \mathrm{H}_{3} \mathrm{O}_{4}\) (d) \(\mathrm{C}_{4} \mathrm{H}_{4} \mathrm{O}_{4}\)

Two elements \(\mathrm{X}\) (atomic weight \(=75\) ) and \(\mathrm{Y}\) (atomic weight \(=16\) ) combine to give a compound having \(75.8 \% \mathrm{X}\). The formula of the compound is (a) \(\mathrm{X}_{2} \mathrm{Y}_{2}\) (b) \(\mathrm{X}_{2} \mathrm{Y}_{3}\) (c) \(\mathrm{X}_{2} \mathrm{Y}\) (d) XY

The percentage of sulphur in an organic compound whose amount of \(0.32 \mathrm{~g}\) produces \(0.233 \mathrm{~g}\) of \(\mathrm{BaSO}_{4}\) (Atomic weight of \(\mathrm{Ba}=137, \mathrm{~S}=32\) ) is (a) \(1.0\) (b) \(10.0\) (c) \(25.3\) (d) \(32.1\)

\(116 \mathrm{mg}\) of a compound on vapourisation in a Victor Meyer's apparatus displaces \(44.8 \mathrm{~mL}\) of air measured at STP. The molecular mass of the compound is (a) \(58 \mathrm{~g}\) (b) \(48 \mathrm{~g}\) (c) \(116 \mathrm{~g}\) (d) \(44.8 \mathrm{~g}\)

Two organic compounds \((\mathrm{X})\) and \((\mathrm{Y})\) both containing only \(\mathrm{C}\) and \(\mathrm{H}\) yields on analysis, the same percentage composition by mass \(\mathrm{C}=92.3 \%\) and \(\mathrm{H}=7.7 \%\) (X) decolourizes bromine water and (Y) does not. Identify \((\mathrm{X})\) and \((\mathrm{Y})\) (a) \(\mathrm{X}=\mathrm{C}_{2} \mathrm{H}_{2}, \mathrm{Y}=\mathrm{C}_{3} \mathrm{H}_{\mathrm{B}}\) (b) \(\mathrm{X}=\mathrm{C}_{2} \mathrm{H}_{4}^{2}, \mathrm{Y}=\mathrm{C}_{2}^{3} \mathrm{H}_{6}\) (c) \(\mathrm{X}=\mathrm{C}_{6} \mathrm{H}_{6}, \mathrm{Y}=\mathrm{C}_{2} \mathrm{H}_{2}\) (d) \(\mathrm{X}=\mathrm{C}_{2} \mathrm{H}_{2}, \mathrm{Y}=\mathrm{C}_{6} \mathrm{H}_{6}\)

In the reaction, \(\mathrm{CH}_{4}+2 \mathrm{O}_{2} \longrightarrow \mathrm{CO}_{2}+2 \mathrm{H}_{2} \mathrm{O}\), the amount of oxygen needed to completely bum \(4.0 \mathrm{~g}\) of \(\mathrm{CH}_{4}\) is (a) 4 (b) \(8 \mathrm{~g}\) (c) \(16 \mathrm{~g}\) (d) \(32 \mathrm{~g}\)

\(0.1914 \mathrm{~g}\) of an organic acid is dissolved in about 20 \(\mathrm{mL}\) of water \(25 \mathrm{~mL}\) of \(0.12 \mathrm{~N} \mathrm{NaOH}\) is required for the complete neutralization of the acid solution. The equivalent weight of the acid is (a) \(63.8\) (b) \(64.0\) (c) \(65.8\) (d) \(66.2\)

An alkane has a C/H ratio of \(5.1428\) by mass. Its molecular formula is (a) \(\mathrm{C}_{5} \mathrm{H}_{12}\) (b) \(\mathrm{C}_{6} \mathrm{H}_{14}\) (c) \(\mathrm{C}_{\mathrm{s}} \mathrm{H}_{18}\) (d) \(\mathrm{C}_{\gamma} \mathrm{H}_{10}\)