19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
In the reaction o o ½ K O KO ->
An oxidation process involves
In the reaction, SO 2H S 3S 2H O -> the substance oxidized is
In the Kjeldahl's method for estimation of nitrogen present in a soil sample, ammonia evolved from 0.75g of sample neutralised 10 mL of 1M H SO . The percentage of nitrogen in the soil is (CBSE AIPMT 2014)
Lassaigne's test is used in qualitative analysis to detect (UK PMT 2014)
In which among the following compounds presence of nitrogen cannot be detected by Lassaigne's method? (MHT CET 2014)
Which one of the following methods can be used to separate a mixture of ortho and para-nitrophenols? (EAMCET 2014)
A liquid which decomposes at its boiling point can be purified by (Manipal 2014)
Correct pair of compounds, which gives blue colouration/ precipitate and white precipitate, respectively, when their Lassaigne’s test is separately done is (West Bengal JEE 2013)
The colour of the solution/precipitate obtained in the elemental analysis of an organic compound and the molecule/ion responsible for the colour are given below. Choose the incorrectly matched pair: (Kerala PET 2013 )
Kjeldahl's method cannot be used for the estimation of nitrogen in (AFMC 2013)
In the estimation of sulphur by Carius method 0.480 g of an organic compound given 0.699g of barium sulphide. The percentage of sulphur in this compound is (atomic masses : Ba = 137.5 = 32 and O = 16) (Kerala PET 2012)
Presence of halogen in organic compounds can be detected by using (UP CPMT 2012)
The Lassiaigne’s extract is boiled with conc. HNO3 while testing for halogens. By doing so it (AIPMT Prelim 2011)
1.2 g of organic compound of Kjeldalization liberaze ammonia which consumes 30 cm3 of 1N HCl. The percentage of nitrogen in the organic compound is (KCBT 2011)
1 percent composition of an organic compound A is carbon: 85.71% and hydrogen 14.20% . Its vapour density is 14. Consider the following reaction sequence Cl /H O (i) KCN/EtOH (ii) H O A B C -> -> Identify C (EAMCET 2…
The masses of carbon, hydrogen and oxygen in an organic compound are in the ratio 6: 1: 8 respectively. Which of the following pairs of formulae correspond to the above information? (Kerala CEE 2009) (a) CH O and CH …
In the Duma's method of estimation of nitrogen, the nitrogen in the organic compound is finally converted into (Kerala CEE 2009)
In an organic compound, C 68.5% and H 4.91% . Which empirical formula is correct for it? (CPMT 2009) (a) C H (b) C H O (c) C H O (d) C H O Ans. (b) Sol. Element At. Percent No. of Simple molar wt. composition moles …
A hydrocarbon has carbon and hydrogen. Its molecular weight is 28. Its possible formula would be (AFMC 2009) (a) C H (b) C H (c) CH (d) C H Ans. (b) Sol. Compound Molecular weight C H 12 3 x C H x CH C H x Henc…
Assertion (A): S || NH – C– NH gives red color in Lassaigne’s test Reason (R): Compounds having N along with C give red colour in Lassaigne’s test. (AIIMS2009)
Assertion (A): Oils are purified by steam distillation. Reason (R): The compounds which decompose at their boiling points can be purified by steam distillation. (AIIMS2008)
Assertion (A): During test for nitrogen with Lassaigne’s extract on adding FeCl3 solution sometimes a red precipitate is obtained. Reason (R): Sulphur is also present (AIIMS2007)
Anthracene can be purified by
Steam distillation is used only in case of steam volatile substance. Hence (c) is not correct. 4. Vaccum distillation is used in liquids which decompose at their boiling Point. Hence (d) is incorrect.