Why freshly prepared FeSO4 is used in nitrogen testing ?

Why freshly prepared FeSO4 is used in nitrogen testing ?
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1 Answer

Answer :

Because FeSO4 gets hydrolysed if its solution is stored for long.
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Related questions

Why is an organic compound fused with Sodium for testing nitrogen,halogens and sulphur ?

Description : Why is an organic compound fused with Sodium for testing nitrogen,halogens and sulphur ?

Last Answer : On fusing with sodium metal the elements presents in an organic compounds are converted in to ionic compounds of sodium which are water soluble which can be filtered and detected by the respective tests.

Why Glycerol could not be prepared by steam distillation?

Description : Why Glycerol could not be prepared by steam distillation?

Last Answer : Glycerol decompose at its Boiling point.

How Sodium fusion extract is prepared ?

Description : How Sodium fusion extract is prepared ?

Last Answer : A small piece of dry Sodium metal is heated with a organic compound in a fusion tube for 2 -3 minutes and the red hot tube is plunged in to distilled water contained in a china dish. The contained of the china dish is boiled ,cooled and filtered. The filtrate is known as Sodium fusion extract.

0.257g of organic substance was heated with conc. sulphuric acid and then distilled with excess of strong alkali .the ammonia gas evolved was absorbed in 50ml of .1M HCl which required 23.2ml of c for neutralization at the end of the process. Determine the % of nitrogen in the compound ?

Description : 0.257g of organic substance was heated with conc. sulphuric acid and then distilled with excess of strong alkali .the ammonia gas evolved was absorbed in 50ml of .1M HCl which required 23.2ml of c for neutralization at the end of the process. Determine the % of nitrogen in the compound ?

Last Answer : A. Vol of 0 .1M HCl taken = 50ml Vol of .1MNaOH used for neutralization of unused acid=23.2ml Now, 23.2 ml of .1MNaOH =23.2ml of .1MHCl Vol of .1MHCl unused=23.2ml Vol of .1MHCl required ... NH3 solution contain nitrogen = 14*26.8/10*1000 Percentage of Nitrogen=14*26.8*100/10*1000*.257 =14.6%

In DNA and RNA nitrogen is present in the ring system. Can Kjeldahl method can be used for the estimation of nitrogen present in these ?give reasons

Description : In DNA and RNA nitrogen is present in the ring system. Can Kjeldahl method can be used for the estimation of nitrogen present in these ?give reasons

Last Answer : In DNA and RNA nitrogen is present in heterocyclic rings. Kjeldahl method can not be used to estimate nitrogen present in the ring because cannot be completely converted in to (NH4)2SO4 during digestion. Therefore Kjeldahl method cannot be used to estimate nitrogen present in DNA and RNA.

0.3780g of organic chloro compound gave 0.5740g of silver chloride in carius estimation .Calculate the percentage of chlorine present in the compound.

Description : 0.3780g of organic chloro compound gave 0.5740g of silver chloride in carius estimation .Calculate the percentage of chlorine present in the compound.

Last Answer : % of chlorine = 35.5*mass of AgCl formed * 100/143.5 * mass of the substance = 35.5*0.5740*100/143.5*0.3780 = 19.6 %

In an estimation of sulphur by carius method 0.468 g of an organic compound gave 0.668 g of barium sulphate. Find the percentage of sulphur in the compound.

Description : In an estimation of sulphur by carius method 0.468 g of an organic compound gave 0.668 g of barium sulphate. Find the percentage of sulphur in the compound.

Last Answer : Mass of the compound = 0.468 g Mass of the barium sulphate = 0.668 g % of sulphur = 32 X Mass of barium sulphate X 100/ 233 X Mass of the compound = 32 x 0.668x100/ 233 x0.468 = 19.60 %

An organic compound contain 69% carbon and 4.8% hydrogen, the remaining being oxygen. Calculate the masses of carbon dioxide and water produced when 0.20g of this substance is subjected to complete combustion.

Description : An organic compound contain 69% carbon and 4.8% hydrogen, the remaining being oxygen. Calculate the masses of carbon dioxide and water produced when 0.20g of this substance is subjected to complete combustion.

Last Answer : Calculation of mass of CO2 produced: Mass of compound =0.20g %C =12 x C 69=12*mass of CO2 formed*100/44*0.2 Mass of CO2 formed =69*44*.2/12*100 = 0.506g Similarly, % H =2* mass of H2Oformed*100/18* ... compound 4.8=2* mass of H2Oformed*100/18* 0.2 Mass of H2Oformed =4.8*18*0.2/2*100 =0.0864g

What is the principle of Dumas method for the estimation of N in the organic compound?

Description : What is the principle of Dumas method for the estimation of N in the organic compound?

Last Answer : In Dumas method , Nitrogen present in organic compound on heating with CuO release free nitrogen gas ,which collected by the downword displacement of KOH. From the voiume of nitrogen gas collected at STP, Nitrogen could be estimated.

Name the technique used to separate water from carbon tetrachloride?

Description : Name the technique used to separate water from carbon tetrachloride?

Last Answer : Water and carbon tetrachloride could be separated using a separating funnel, since the two are immiscible and heavier carbon tetrachloride forms the lower layer.

It is advisable to prepare Lassaignes extract in distilled water why?

Description : It is advisable to prepare Lassaignes extract in distilled water why?

Last Answer : Tap water usually contain dissolved chlorine which gives test for halogen.

Name a decolorizing agent commonly used to decolorize the organic compound?

Description : Name a decolorizing agent commonly used to decolorize the organic compound?

Last Answer : Activated Charcoal.

What is the common criteria for purifying organic compound ?

Description : What is the common criteria for purifying organic compound ?

Last Answer : Their Fixed Melting and Boiling point.

What indication is given by blood red coloration in Lassaigns test ?

Description : What indication is given by blood red coloration in Lassaigns test ?

Last Answer : Presence of both N and S together in an organic compound.

A liquid with high boiling point decomposes on simple distillation but it can be steam distilled for its purification .Explain how is it possible?

Description : A liquid with high boiling point decomposes on simple distillation but it can be steam distilled for its purification .Explain how is it possible?

Last Answer : In steam distillation boiling occurs when vapour pressure of organic compound & steam becomes equal to atmospheric pressure. As vapour pressure of water is higher than the organic liquid. ... organic liquid vaporizes at a temperature below its boiling point in steam distillation without decomposing.

Two liquids (A)and(B)are separated by fractional distillation, the boiling point of (A) is less than (B).which liquid comes out first in distillate? Explain.

Description : Two liquids (A)and(B)are separated by fractional distillation, the boiling point of (A) is less than (B).which liquid comes out first in distillate? Explain.

Last Answer : The liquid (a) comes out first in distillate. On boiling the vapours of lower boiling component are formed first.

Give principles behind – i) Crystallization ii) Chromatography

Description : Give principles behind – i) Crystallization ii) Chromatography

Last Answer : i) impure solid is dissolved in minimum amount of solvent, insoluble impurities are filtered out .solution containing soluble impurities is heated till crystallization point. The crystals of pure substance separate ... is solid the basis is adsorption and when it is liquid the basis is partition.

Name a suitable technique of separation of the components from a mixture of calcium sulphate and camphor.

Description : Name a suitable technique of separation of the components from a mixture of calcium sulphate and camphor.

Last Answer : The components from a mixture of calcium sulphate and camphor can be separated by the process of sublimation.

Explain ,why an organic liquid vapourises at a temperature below its boiling point in steam distillation?

Description : Explain ,why an organic liquid vapourises at a temperature below its boiling point in steam distillation?

Last Answer : Because for boiling to occur vapour pressure of organic compound & steam should be equal to atmospheric pressure. As vapour pressure of water is higher than organic liquid. Therefore, organic liquid vaporizes at a temperature below its boiling point in steam distillation .

By which method aniline can be purified?

Description : By which method aniline can be purified?

Last Answer : By steam distillation.

Will CCl4 give white ppt.of AgCl on heating with AgNO3?

Description : Will CCl4 give white ppt.of AgCl on heating with AgNO3?

Last Answer : No, CCl4 being covalent compound does not give white ppt.of AgCl on heating with AgNO3

Explain the principle of paper chromatography.

Description : Explain the principle of paper chromatography.

Last Answer : Paper chromatography is based on the difference in the rates at which the components of a mixture are adsorbed. The material on which different components are adsorbed is called ... compounds are adsorbed on stationary phase at different rates and separated by differential adsorption method.

Write a short note on differential extraction.

Description : Write a short note on differential extraction.

Last Answer : When an organic compound is present in an aqueous medium it is separated by shaking it with organic solvent in which it is more soluble than in water. The aqueous solution is mixed with ... and organic layer is separated. The process is repeated several times and pure organic compound is separated.

Under what conditions can the process of steam distillation is used?

Description : Under what conditions can the process of steam distillation is used?

Last Answer : Steam distillation is used to purify the liquids which are steam volatile and insoluble in water and the liquids are not miscible with each other.

How we can separate coloured components?

Description : How we can separate coloured components?

Last Answer : By chromatography.

What is sublimation? What kind of organic compounds can be purified by this technique?

Description : What is sublimation? What kind of organic compounds can be purified by this technique?

Last Answer : Process of change of solid substance directly into vapour phase without the intermediate liquid state is called sublimation. This technique is used to separate sublimable compounds.Like camphor ,ammonium chloride.

Lassaigne’s test is not shown by diazonium Salt. Why?

Description : Lassaigne’s test is not shown by diazonium Salt. Why?

Last Answer : On heating diazonium Salts loses Nitrogen and could not fuse with the sodium metal therefore diazonium salt do not show Positive Lassaigne’s test for nitrogen.

How will you separate a mixture of o-nitrophenol and p- nitrophenol ?

Description : How will you separate a mixture of o-nitrophenol and p- nitrophenol ?

Last Answer : o-nitrophenol is steam volatile therefore it can be separated by Steam distillation.

Suggest a method to purify a liquid which decomposes at its boiling point.

Description : Suggest a method to purify a liquid which decomposes at its boiling point.

Last Answer : The process Distillation under reduced pressure is used to purify a liquid which decomposes at its boiling point.

Give three point of difference between Resonance and Inductive effect.

Description : Give three point of difference between Resonance and Inductive effect.

Last Answer : Ans. Resonance: a. The resonance involves pi-electrons or lone pair of electrons. b. This effect moves all along the length of the conjugate system. c. This result in complete transfer ... become negligible from the fourth carbon atom onwards. c. This effect causes slight displacement of electrons.

Which of the two: O2NCH2CH2O– or CH3CH2O– is expected to be more stable and why?

Description : Which of the two: O2NCH2CH2O– or CH3CH2O– is expected to be more stable and why?

Last Answer : Ans. O2NCH2CH2O– is more stable than CH3CH2O– because NO2 group has –I effect and hence it tends to disperse the negative charge on the oxygen atom. In contrast, CH3CH2 has +I effect. It, therefore, tends to intensify the negative charge and hence destabilizes it.

Give any two consequence of hyperconjugation effect?

Description : Give any two consequence of hyperconjugation effect?

Last Answer : Ans: Consequence of hyperconjugation effect:- 1. Shortening of c-c single bond adjacent to multiple bond. 2. Stability of methylated alkenes.

Write the metamer of diethyl ether. What is its IUPAC name?

Description : Write the metamer of diethyl ether. What is its IUPAC name?

Last Answer : Ans.1-methoxypropane, CH3OCH2CH2CH3 or 2-methoxypropane,CH3OCH(CH3)2

In which C–C bond of CH3CH2CH2Br, the inductive effect is expected to be the least?

Description : In which C–C bond of CH3CH2CH2Br, the inductive effect is expected to be the least?

Last Answer : Ans. The magnitude of inductive effect decreases with distance and hence the effect is least in C2-C3 bond.

Explain electromeric effect, resonance effect and hyperconjugation.

Description : Explain electromeric effect, resonance effect and hyperconjugation.

Last Answer : Ans: Electromeric effect is defined as the complete transfer of a shared pair of π-electrons to one of the atoms joined by a multiple bond on the demand of an attacking reagent. It ... with the attached unsaturated system or with the unshared p orbital. Hyperconjugation is a permanent effect.

Give one examples of o and p directing group.

Description : Give one examples of o and p directing group.

Last Answer : Ans. The groups which direct the incoming group to ortho and para positions are called ortho and para directing groups. For example: Phenol

Trans-Pent-2-ene is polar while trans-but-2-ene is non polar. Explain.

Description : Trans-Pent-2-ene is polar while trans-but-2-ene is non polar. Explain.

Last Answer : Ans. In trans-but-2-ene, the dipole moment of two C-CH3 bonds are equal and opposite and hence they exactly cancel out each other. Thus trans-but-2-ene is non polar. In trans-pent-2-ene, ... cancel out each other and hence trans-pent2-ene has a small value of dipole moment and thus is polar.

What type of fissions is possible in a Covalent Bond?

Description : What type of fissions is possible in a Covalent Bond?

Last Answer : Ans: Homolytic and Heterolytic

Define metamers with example.

Description : Define metamers with example.

Last Answer : Ans: It arises due to different alkyl chains on either side of the functional group in the molecule. For example, C4H10O represents methoxypropane (CH3OC3H7) and ethoxyethane (C2H5OC2H5).

Why does benzene undergo electrophilic substitution reactions easily and nucleophilic substitutions with difficulty?

Description : Why does benzene undergo electrophilic substitution reactions easily and nucleophilic substitutions with difficulty?

Last Answer : Ans. Due to the presence of an electron cloud containing 6 pi electrons above and below the plane of the ring, benzene is a source of electrons. Consequently, it attracts ... . As a result, benzene undergoes electrophilic substitution reactions easily and nucleophilic substitution with difficulty.

Discuss about structural isomerism and stereoisomerism.

Description : Discuss about structural isomerism and stereoisomerism.

Last Answer : Ans. Structural Isomerism: Compounds having the same molecular formula but different structure i.e. different arrangement of atoms within the molecule are called structural isomers and the phenomenon is ... or groups in space are called stereo isomers and the phenomenon is called as stereoisomerism.

Out of benzene, m–dinitrobenzene and toluene which will undergo nitration most easily and why?

Description : Out of benzene, m–dinitrobenzene and toluene which will undergo nitration most easily and why?

Last Answer : Ans. -CH3 group is electron donating while –NO2 group is electron withdrawing. Therefore, maximum electron density will be in toluene, followed by benzene and at least in m-dinitrobenzene. Therefore, the ease of nitration decreases in the order: Toluene> benzene> m-dinitrobenzene

Out of pentane, 2-methylbutane and 2,2-dimethylpropane which has the highest boiling point and why?

Description : Out of pentane, 2-methylbutane and 2,2-dimethylpropane which has the highest boiling point and why?

Last Answer : Ans. Pentane having a continuous chain of five carbon atoms has the highest boiling point (309.1K) whereas 2,2 - dimethylpropane boils at 282.5K. With increase in number ... and therefore weak intermolecular forces between spherical molecules, which are overcome at relatively lower temperatures

Among Cis and Trans structure of Hex-2-ene which has higher boiling point and why?

Description : Among Cis and Trans structure of Hex-2-ene which has higher boiling point and why?

Last Answer : Ans: The dipole moment of a molecule depends upon dipole-dipole interactions. Since cis-isomer has higher dipole moment, therefore it has higher boiling point.

What effect does branching of an alkane chain has on its boiling point?

Description : What effect does branching of an alkane chain has on its boiling point?

Last Answer : Ans. As the branching increases, the surface area of an alkane approaches that of a sphere. Since a sphere has minimum surface area, therefore, Vander Waal forces of attraction are minimum and hence the boiling point of the alkane decreases with branching.

Define conformers/rotamers.

Description : Define conformers/rotamers.

Last Answer : Ans1- . The spatial arrangements of atoms which can be converted into one another by rotation around a C-C single bond are called conformations or conformers or rotamers.

Name two isomers of butanol? Which has higher boiling point?

Description : Name two isomers of butanol? Which has higher boiling point?

Last Answer : Ans. n-butanol and 2-methyl propan-2-ol.Butanol has the higher boiling point as the branching increases the surface area of the molecule decreases so the boiling point decreases.

Write the IUPAC name for: (CH3)2CHCH(OH)CH2C(CH3)3,identify the functional group and type of compound.

Description : Write the IUPAC name for: (CH3)2CHCH(OH)CH2C(CH3)3,identify the functional group and type of compound.

Last Answer : Ans. 2,5,5-trimethylhexan-3-ol, alcohol, secondary alcohol

Write the IUPAC of molecule with the formula C3 H8?

Description : Write the IUPAC of molecule with the formula C3 H8?

Last Answer : Ans. propane

What is the hybridization of carbon atoms in alkanes ?

Description : What is the hybridization of carbon atoms in alkanes ?

Last Answer : Ans. Sp3