0.3780 g of an organic compound gave 0.5740 g of silver chloride in Carius estimation. Calculate the percentage of chlorine in the compound.
Mass of the compound = 0.3780 g
Mass of silver chloride = 0.5740 g
Compounds with same molecular formula but differing in their structures are said to be structural isomers. What type of structural isomerism is shown by
Why is an organic compound fused with Sodium for testing nitrogen, halogens and sulphur?
Differentiate between the principle of estimation of nitrogen in an organic compound by (i) Dumas method (ii) Kjeldahl’s method.
Suggest a suitable technique for separating naphthalene from kerosene oil present in a mixture.
0 .12 g of an organic compound containing phosphorous gave 0.22 g of Mg2 P2O7 by usual analysis. Calculate the percentage of phosphorous in the compound.
Hyperconjugation involves delocalization of .
(a) electrons of carbon-hydrogen σ bond of an alkyl group directly attached to an atom of unsatUrated system.
(b) electrons of carbon-hydrogen σ bond of alkyl group directly attached to the positively charged carbon atom.
(c) π-electrons of carbon-carbon bond.
(d) lone pair of electrons.
Electronegativity of carbon atoms depends upon their state of hybridization. In which of the following compounds, the carbon marked with asterisk is most electronegative?
In DNA and RNA, nitrogen atom is present in the ring system. Can Kjeldahl method be used for the estimation of nitrogen present in these? Give reasons.
By mistake, an alcohol (boiling point 97 °C) was mixed with a hydrocarbon (boiling point 68 °C). Suggest a suitable method to separate the two compounds. Explain the reason for your choice.
In an estimation of sulphur by Carius method, 0.468 of an organic sulphur compound gave 0.668 g of barium sulphate. Find the percentage of sulphur in the compound.
Covalent bonds can undergo fission in two different ways. The correct representation involving the heterolytic fission of CH3 – Br is
For testing halogens in an organic compound with AgN03 solution, sodium extract (Lassaigne's extract) is acidified with dilute HN03. What will happen if a student acidifies the extract with dilute H2S04 in place of dilute HN03?
Draw formulas for the first five members of each homologous series beginning with the following compounds,
(a) H—COOH (b) CH3COCH3 (c) H—CH=CH2
Give equation for the following:
(i) Electrophilic Substitution
(ii) Nucleophilic Substitution
(a) Which is more suitable method for the purification of a compound in liquid state which decomposes at or below its boiling point?
(b) How will you separate a mixture of ammonium chloride and common salt?
How will you separate a mixture of two organic compounds which have different solubilities in the same solvent?
Electrophilic addition reactions proceed in two steps. The first step involves the addition of an electrophile. Name the type of intermediate formed in the first step of the following addition reaction.
H3C-HC = CH2 + H+→ ?
(a) 2 °Carbanion
(b) 1 ° Carbocation
(c) 2 ° Carbocation
(d) l °Carbanion
Which of the following compounds contain all the carbon atoms in the same hybridization state?
Match the type of mixture of compounds in Column I with the technique of separation/purification given in column II.
| Column I | Column II |
| (a) Two solids which have different solubilities in a solvent and which do not undergo reaction when dissolved in it. | (1) Steam distillation |
| (b) Liquid that decomposes at its boiling point | (2) Fractional distillation |
| (c) Steam volatile liquid | (3) Simple distillation |
| (d) Two liquids which have boiling points close to each other | (4) Distillation under reduced pressure |
| (e) Two liquids with large difference in boiling points. | (5) Crystallisation |
Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen, sulphur and halogens.
(a) What is the basic principle involved in the estimation of nitrogen by Dumas method.
(b) In a Dumas nitrogen estimation method, 0.30 g of an organic compound gave 50 cm3 of N2 collected at 300 K and 715 mm Hg pressure. Calculate the percentage composition of nitrogen in the compound. (Vapour pressure of water at 300 K is 15 mm Hg)
What is the relationship between the members of following pairs of structures? Are they structural or geometrical isomers or resonance contributors?
Explain, why an organic liquid vaporises at a temperature below its boiling point in its steam distillation ?
Nucleophile is a species that should have
(a) a pair of electrons to donate
(b) positive charge
(c) negative charge
(d) electron deficient species
Indicate the a- and n-bonds in the following molecules:
C6H6 , C6H12, CH2Cl2, CH=C=CH2, CH3NO2, HCONHCH3
Why is nitric acid added to sodium extract before adding silver nitrate for testing halogens ?
Why is a solution of potassium hydroxide used to absorb carbon dioxide evolved during the estimation of carbon present in an organic compound?
In which of the following compounds the carbon marked with asterisk is expected to have greatest positive charge?
Three students, Manish, Ramesh and Rajni, were determining the extra elements present in an organic compound given by their teacher. They prepared the Lassaigne's extract (LE) independently by the fusion of the compound with sodium metal. Then they added solid FeS04 and dilute sulphuric acid to a part of Lassaigne's extract. Manish and Rajni obtained Prussian blue colour bit Ramesh got red colour. Ramesh repeated the test with the same Lassaigne's extract, but again got red colour only. They were surprised and went to their teacher and told him about their observation. Teacher asked them to think over the reason for this. Can you help them by giving the reason for this observation? Also, write the chemical equations to explain the formation of compounds of different colours.
Resonance structures of propenal are given below. Which of these resonating structures is more stable? Give reason for your answer.
